Local elections are due to take place next Thursday where many commentators believe Labour is set to make significant gains. While local polls are often influenced by parochial concerns, the results will inevitably prompt speculation about how this affects the two main parties at Westminster.

In this Lexcomm we take a look at where elections are happening; the key battlegrounds; initial indications about how the parties might fare; and what would constitute a good or a bad night for Theresa May and Jeremy Corbyn.

Where are elections taking place?

150 councils across the breadth of England are electing new councillors, with six mayoral elections: the City Mayor in Sheffield City Region and five directly mayors in the Hackney, Lewisham, Newham, Tower Hamlets and Watford councils.

Every seat in all 32 London boroughs is being contested, as well as every seat in the metropolitan districts of Birmingham, Manchester, Leeds and Newcastle. A third of seats are up for grabs in 30 other metropolitan districts, including Liverpool, Sheffield, Sunderland and Wigan.

What are the key battlegrounds?

London is the key battleground with Labour looking to take control of Barnet, Wandsworth and Westminster. The capital will also provide a test for the strength of any Liberal Democrat revival, with the party looking to recapture councils in the affluent suburbs of Kingston and Richmond.

Outside London, a Liberal advance could cost the Conservatives control of flagship councils including Trafford and Swindon.

Elections in the Midlands and North will meanwhile test the strength of Labour’s national position. Key councils to watch are Amber Valley, Calderdale, Dudley and Newcastle-under-Lyme.

What is expected?

The Conservatives are braced for losses. Rob Hayward, the Tory psephologist, recently predicted that they will lose about 100 council seats of their 612. The party is especially concerned about its performance in London, where factors including Brexit and race are likely to do damage.

While those issues look set to boost Labour support, other factors could work against the party. The recent row over anti-Semitism has been damaging to the party and to Jeremy Corbyn personally, and may undermine Labour’s performance in areas with a large Jewish vote – notably Barnet.

The collapse of UKIP could also work against Labour. The last time this set of local elections was contested, in 2014, UKIP won 17% of the vote. Since then the party has descended into disarray. A decisive factor in next week’s poll will be where those previous UKIP voters swing to. It won’t be a factor in London, where UKIP has never been strong, but it could stall Labour’s advance in the old industrial Midlands and North of the country.

More generally, the strength of Labour’s performance in 2014 means the party is already at high tide in many of the councils being contested. That makes it difficult to add any significant new gains.

What is a good/bad night for the Conservatives?

Losses are expected though if they exceed 100 seats it would look like a very bad night. But the bigger long term issue is where they occur. Many of the local elections are taking place in constituencies where the Tories currently have MPs. As Stephen Bush of the New Statesman recently pointed out, a retreat in council wards in the Hastings and Putney constituencies would spell danger for MPs like Justine Greening and Amber Rudd.  Losing control of flagship councils would also erode the Conservative Party’s political base and further undermine confidence in Theresa May’s leadership.

  • Good night: Retain control of Barnet and most other London councils they control, and defy Labour progress in other parts of the country
  • Bad night: Lose Barnet and Wandsworth to Labour in London, and fail to stem Labour’s advance in the Midlands and North
  • Terrible night: Lose Amber Valley, Bexley, Hillingdon and Westminster to Labour; and lose control of Trafford and Swindon

What is a good/bad night for Labour?

Labour will be looking to win nearer to 200 seats and take control of a number of flagship councils, especially in the London area. However, a key test in looking ahead to the next general election will be whether the party can also make progress in its old industrial heartlands and in urban areas that it held in the past.

  • Very good night: Take control of Bexley, Hillingdon and other London councils; make significant gains in Swindon and Trafford; take control of Amber Valley, Calderdale and Newcastle-under-Lyme
  • Good night: Win Barnet, Tower Hamlets, Wandsworth and Westminster; secure other council gains in old industrial areas outside London including Dudley and Carlisle
  • Bad night: Fail to take any councils in London apart from Tower Hamlets; and unable to make progress outside of London