Hillcroft Development 22/00607/FUL - deadline 22 March

Brown long eared bat recorded within its emergence time at Hillcroft


37 years ago, when looking after my young son, I attended short courses at Hillcroft. I remember delighting in the work of Berthe Morisot in the history of Women in Art courses. I was fortunate in attending a long running creative writing class, where Jacqueline Wilson was a fellow pupil. 

In later years, I attended the first Hillcroft Open House weekend and we were told about: the original mosaic floor (marked in the top right - hand side of the  plan below); the turret in the south-east quadrant; and as we sat outside the window, we were on a plane with a detached underground tunnel running perpendicular to the house.

Intrigued, I introduced myself as a licensed bat worker and expressed an interest in the tunnel, which I was encouraged to put in writing to the Principal; unfortunately, the investigation was never realised as I was told that tunnels have to be blocked as they are dangerous (although blocking usually increases the danger as gases build up and cannot escape).

Consultation and planning application

 Hillcroft was later taken over by RHACC. Fast forward to last August and the Hillcroft consultation The full impact of the planning application was presented 23.2.22. The consultation only serving to warn the developers how to 'dress up' the unmodified assault on our greenspace for the: -

Floorplan of Hillcroft (formerly The Gables).

Demolition of Powell House; Construction of a replacement college building comprising two storeys and ancillary single storey building (Use Class F.1); Partial demolition, conversion and extension of the Listed Building ‘Hillcroft College Including Former Stable Block’ to provide 17 residential dwellings (Use Class C3); Construction of a new building in the setting of the Listed Building comprising two storeys and providing 4 residential dwellings (Use Class C3); Construction of an additional new building comprising four storeys and providing 13 residential dwellings(Use Class C3); with associated access, landscaping, drainage and other works.

Here I deal with the bat report (work in progress). With a site of this size, the impacts of such magnitude, with a  large number of bat species recorded (8) and an important site for bats nearby (Seething Wells) is this document really fit for purpose?

 Desk study

The first step in a Bat Habitat Assessment is the Desk Study. This is where records are obtained from the Bat Group or the Greenspace Information for Greater London. Nearby bat roosts and species information is crucial to the understanding of the bat potential of the site. With the site of this size, it is possible that bat roosts have been investigated in the past by people like myself and records already exist. So where is this information?

A Desk Study also provides information regarding sites important for bats nearby. Bats have multiple roosts that they use at different times of the year; they commute along dark corridors to their various feeding areas. Bat habitat use, foraging strategy and items of prey, differs according to  the species and should be qualified. 

Nine species of bat have been recorded foraging over the Filter Beds at Seething Wells. Larger tree dwelling species have no roost  availability at the Filter Beds but they are dependent on it for foraging, especially in the early part of the breeding season. Taking out large numbers of trees, especially those in the lower categories, as they plan to do at Hillcroft, may wipe out the roost resource for the Leisler's and noctule bats discovered using Hillcroft. Both these species are rare in London and Leisler's bat is rare nationally (see below).

 Bat habitat assessment

Strangely, the bat report contained no mention of the tunnels. This would be the second point of interest (after a Desk Study) in any Bat Habitat Assessment. As the report is presented, there is no evidence of a recent Bat Habitat Assessment being undertaken in the current round of Phase 2 emergence surveys, with an expired survey from 2018 not presented to the planning file. Powell House was downgraded conveniently to negligible for bats. 

The assessment is a vital step where the buildings surveyors crawl through the loft spaces looking for any signs of bat use and occupation (from feeding remains (moth wings) or droppings from feeding/roosting areas).

The assessment is where decisions are made about: the number of surveyors that are required for the survey and the features optimised for bats that should be concentrated on. This process should be transparent and included in the bat report, contain photographs of the main features, aided by a scoring system & appropriately quantified surveys on each building or tree(s). Instead, this stage is alluded to at 5.4.

Emergence times

Normally, the emergence surveys are expounded in the results and then evaluated in the Discussion. Guidelines are given by the Bat Conservation Trust Survey Guidelines endorsed by the CIEEM for surveyors and the times of bat emergence are important in ascertaining whether a bat has just left a roost or has travelled from an offsite location. 

A brown long-eared bat leaves its roost only when it is truly dark 44 - 60 minutes after sunset and a pipistrelle up to 20 minutes after sunset so these timings are important. But they are not presented. No tables are provided with the surveys. 

Bat species recorded

They are not even clear about the number of species or when they surveyed. The Summary gives June as for the initial survey but the main report states July. Read 1.3 yourself and see if you can make sense of when it was surveyed. If the month of June was not included in the emergence surveys,  a roost could have easily been missed. In the Discussion there are 5 bat species recorded and two of these do not follow the convention of being spelt with the required uppercase letter, as if there is no familiarity with the species:

But during the emergence surveys they found 8 species: soprano, common and Nathusius' pipistrelles; brown long-eared bat; noctule and the closely related Leisler's bat; a bat from the genus Myotis and natterer's bat. Look what happens when we obtain a distribution map of Natterer's bat. They are absolutely rare in the borough they have been recorded at three places in recent years (two on the borough boundaries). In 2003 Surrey University were invited to the Fishponds at 4am to record this species, which disappeared after the Brown's Road Flood Diversion Scheme was implemented.

 Brown Long-eared bat

I will reserve my comments to just one further species found during the surveys: the brown long-eared bat. One was recorded at 20.25 during the September 6th survey, which is sunset + 60 minutes, exactly within its emergence period. We have few records in Kingston: one was recorded along the Pipe Track before the lights went in. It likes old roof voids where it roosts all the year round so could easily be using the voids at Hillcroft as we have no evidence that the lofts have been entered.


So, Hillcroft  has more bat species than any site in the borough other than Seething Wells and Sixty Acre Wood. The report uses Stephanie Wray's evaluation scores to value the site for bats. Yet Table 5 appears  truncated with part of it disappearing with no score produced.  


During their survey common pipistrelles were found using darker areas of the site (6.9) and at 6.12 they state 'The south-eastern corner of the site was favoured by all bat species (common pipistrelle, soprano pipistrelle, noctule, brown long-eared and nathusius pipistrelle). This area of the site is amongst the tree canopy and is not subject to any light pollution'.

Yet at 7.9 they tell us that pipistrelle and noctule bats 'are tolerant of lighting' (without giving an authority). Their 'frequently passing natterer's bat and Leisler's bat' kinda drop off the radar here.

But is this document actually fit for purpose when all of the bat species recorded, also roost in trees, particularly during the mating season. Is the tree survey fit for purpose where the Mitigation (pg 12) conjures an ash tree of moderate value to bats - for the first time - and the veteran oak of high potential is clearly due for removal (even though the authors give us 'hope', that it isn't). What happens when the trees are removed on the insect biomass or the removal of the trees as light shields or potential roost/mating sites.

 If the development goes ahead without proper scrutiny, it will have a severe impact on the bat species using the site, the bat activity in this part of the borough and reduce the numbers of bats seen foraging over the FB's at Seething Wells. The survey has not evaluated the site adequately, as one of the most important in the borough for bats, but with particular regard to brown long-eared, natterer's and Leisler's bat. The increased lighting will also have a severe impact on brown long-eared and natterer's bats. Valuable hibernation sites - the tunnels - could be lost without even a mention within any of the surveys.

Additional concerns raised by C. Mellish

- The application form claims that the proposal won't result in the loss of any residential garden land - how come?

- No affordable housing, skewed viability assessment

- Dropping the emphasis on education for disadvantaged women, as set up by Hillcroft. It also looks like the residential model will end.

- Removal of many trees, including TPO trees. One is at the corner by the station and is a significant street tree for people using the road to the station. It is shown as Grade A in the Design & Access Statement.

- Not using recommended tree assessments, such as CAVAT, to ascertain actual social, environmental and economic value

- No formal Environmental Assessment deemed necessary, just a one day preliminary assessment followed by a bat and reptile check

- Removal of a badger sett and other significant environmental damage

- No reptiles found (hard to believe) but surveys were carried out in one week during September ("missing the March- May survey period")

- No mention of the Victorian tunnel or WW2 bunker in the Heritage Statement, and whether they would be impacted by the development


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