Thousands of new homes could still be approved in Somerset in 2021 if the government acts to end local authorities' planning paralysis.

The four Somerset district councils have been struggling to make decisions on major planning applications since a court ruling which required additional tests to be carried out on developments planned in the county.

The councils have requested assistance from central government to carry out these tests and help them clear this backlog.

If successful, thousands more homes could be approved across the county on top of those permissions already granted.

2020 has seen a number of large housing developments given the go-ahead across Somerset by the four district councils – Mendip, Sedgemoor, Somerset West & Taunton and South Somerset.

These include 675 homes on the A39 Quantock Road in Bridgwater, 235 homes at Sandy's Hill Lane in Frome, 190 homes at Jurston Farm in Wellington, and 94 homes on the A358 Tatworth Road in Chard.

But processing these applications ground to a halt in October following the Dutch N case, concerning phosphate levels within protected landscapes – including the Somerset Levels and Moors.

Following the case, Natural England wrote to all four councils urging them to undertake further assessments before approving any plans which could lead to higher phosphate levels in this area – including large numbers of homes.

The councils estimated in early-December that nearly 800 planning applications had been affected, including developments that would deliver over 11,000 new homes.

The councils wrote to the government asking for a commitment that affordable housing funding would not be lost because of these delays, and demanding £140,000 to pay for extra stuff to deliver these assessments.

Here are 16 developments which should have been decided upon by now – and which could be decided upon in 2021 if this support is provided:

A39 Quantock Road in Bridgwater (354 homes): these proposals by Persimmon Homes Severn Valley are split into two parts: full plans for 114 homes, and outline plans for a further 240 properties. The site lies on the southern side of the A39, immediately to the west of the Quantock Road Cemetery and immediately opposite the Cavanna Homes site.

Lyngford Lane in Taunton (347 homes): it has been more than a year since plans to develop this site were put forward by Barratt Homes and David Wilson Homes. Located near the Nerrols Farm primary school, it will see a new roundabout created at the junction with Cheddon Road, with Lyngford Lane to the south being closed off. Emergency and pedestrian access will be maintained, so parents living on the new site can walk or cycle to school with their children.

Saxonvale in Frome (300 homes and commercial space): formal plans for the council's much-trumpeted regeneration of this brownfield site were submitted in May 2019. In addition to 300 properties, the redevelopment will see the existing 'Western Warehouse' retained for cultural use, as well as new retail and commercial space for bars and restaurants – though concerns have been raised about the site's viability.

B3151 Somerton Road in Street (280 homes): these outline plans have been brought forward by the Ninesquare Trust, a charity based in Baltonsborough which owns this site. The trust has already given out £400,000 in grants and will use the proceeds from the development to fund further grants to local voluntary organisations. Access would be from the north-eastern corner of the site, not far from Millfield School.

A358 Tatworth Road, Chard (263 homes): Persimmon Homes South West originally put forward plans in 2016 for 315 homes on this crucial site within the Chard Eastern Development Area (CEDA). The council urged the developer to "think again" in July 2019 in light of significant local opposition to the proposals, including flood risk, traffic congestion and the design of the houses. The developer has now reduced the number of homes to 263 and reiterated its pledge to deliver the first part of a new road which will eventually connect the A358 to the A30.

Tintinhull Road, Yeovil (185 homes): this site lies a stone's throw from the major Brimsmore development which is currently being built out at Yeovil's north-western edge. Gladman Developments put forward plans in November 2019, showing the homes wrapping around the existing garden centre with a new access onto Tintinhull Road rather than the busy A37 towards Ilchester.

Cheddon Road in Taunton (150 homes): Gladman Developments was originally refused permission for 180 homes on this site in July 2019, with the council's planning committee ruling it would damage the natural environment and was outside the Taunton settlement boundary. The developer submitted the same plans for the same number of homes in October, but has subsequently reduced the number to 150.

Staplegrove West urban extension in Taunton (phase one – 173 homes): around 1,600 homes will be built within the Staplegrove urban extension, which was approved in two parts in October 2017 – Staplegrove West (713 homes) and Staplegrove East (915 homes). These revised plans by Redrow Homes are for the first 173 homes on the western site, with a portion of the spine road that will eventually link the A358 to Kingston Road.

B3168 Station Road, Ilminster (150 homes and employment units): the former Horlicks factory site at Ilminster's western edge has been earmarked for developments for a number of years. Dairygold Co-operative Society Ltd put forward these plans in January 2019 for 150 homes on the northern side of the B3168 Station Road and a range of employment units (including a car showroom and a drive-thru) on the southern side. Concerns have been raised about the flood risk from the River Isle which runs near the site.

B3151 Lower New Road in Cheddar (115 homes): these proposals, put forward by Gladman Developments, would see large amounts of green space retained at the site's western edge, with the homes lining a new access onto the B3151. The site lies opposite the contentious Steart Farm development site, where Sainsbury's put forward plans for a further 60 homes (which the council refused in March, but lost the resulting appeal).

Little Keyford Lane in Frome (70 homes): this development by Wainhomes is a stone's throw to the east of the Sandy's Hill Lane development of 235 homes. The land to the south could come forward for further housing in the future – something the developer has indicated by providing designs of how these 70 homes could connect to other estates. For now, only the land on the western side of Little Keyford Lane is under consideration.

Lympsham Road in Lympsham (50 homes): Strongvox Homes has put forward these plans for the Beavers Lodge Farm site in Lympsham, at the northern tip of the district. The proposed development is located a short distance from the A370 Bridgwater Road, leading to Weston-super-Mare, and will include 20 "local needs affordable homes" – a higher percentage than the council normally expects from a commercially-led development.

Coalpit Lane in Stoke St Michael (47 homes): this village near Shepton Mallet could soon see an extension bolted onto its northern boundary. These homes will be built on the eastern side of Coalpit Lane, north of the existing crossroads. The proximity of the Moons Hill Quarry is likely to play into the developer's hands; they will argue it provides enough employment to make the site sustainable in its own right.

West Camel Road, Queen Camel (43 homes): this proposed development wraps around existing comes on West Camel Road and is within walking distance of Countess Gytha Primary School. The land owned beyond the development extends far beyond the school on the other side of the road – meaning this could be the first phase of a major expansion of this village not far from the A303.

Dancing Lane, Wincanton (39 homes): Hopkins Developments won outline permission on appeal in 2015 to build up to 55 homes on this site near Wincanton Community Hospital. These revised plans reduce this number to 39, with the existing parking for NHS staff being relocated. The council has said it is awaiting on Wessex Water's plans to improve the site's drainage before it can make a decision – but this information is expected imminently.

Hamp Bridge in Bridgwater (36 homes and one office): this site was until recently the home of Somerset Bridge Primary School, which is now located on Stockmoor Drive. The vacant site and former school buildings were badly damaged by a fire in September 2019. This brownfield redevelopment by 3C Commercial Ltd will see the buildings and playing fields turned into 36 homes, with an office being created at the western edge and two play areas.