Theresa May faces a major test of her leadership as English voters go to the polls in the local elections today.

Some commentators predict a wipeout for the Conservatives, while others suggest the antisemitism scandal will cost Jeremy Corbyn's Labour party at the ballot box.

Labour hopes to make major gains in London, while the Tories fear losses in Remain-supporting parts of the country.

Here are the key battlegrounds that could decide May's future as prime minister.

LONDON — British voters are going to the polls in councils and regions across the country to vote in the latest round of UK local elections, in what will be a major test of Theresa May's leadership.

Polls opened at 07:00 and will close at 22:00 in 150 English councils, with all of London's 32 boroughs up for grabs. A total of 4,500 seats are being contested across the country.

The prime minister has had a difficult six months, losing four members of her cabinet and suffering a growing number of parliamentary defeats.

As a result, some commentators predict May's Conservative party could suffer a wipeout in the capital, while others suggest Jeremy Corbyn's Labour party could fail to make the gains it needs to be on course to form a government.

The results, which will start to come in in the early hours of Friday morning, will be a huge test of May's authority with some Conservative MPs telling Business Insider that there could be an immediate reckoning for the PM.

Sir John Curtice, Britain's best-known pollster, told BI that May could be saved by Leave-voting areas — particularly those in the north of England — shifting to the Conservatives.

Here are the five key battlegrounds that could ultimately decide the fate of the prime minister this week.

Wandsworth

Wandsworth, London. Willy Barton / Shutterstock

The biggest fight is taking place in the capital and particularly in the Conservative-controlled borough of Wandsworth, south London. The Conservatives have been in power here since 1974. It was famously Margaret Thatcher's favourite council and has the lowest tax rate of any council in the country. It is a quintessential example of the sort of urban heartland where the Conservatives have held out despite Labour's growing support in metropolitan areas. A Labour victory here would be a fantastic result for Corbyn and a huge blow to Prime Minister May.

Simon Hogg, the Labour leader in Wandsworth, recently put the party's chances at "50/50" in an interview with The Guardian. Talking points on the ground include the housing crisis and lack of affordable accommodation — an issue which shows no sign of going away despite the government's efforts — and, of course, Brexit. Wandsworth voted to stay in the European Union and the prime minister's refusal to adopt a softer Brexit is not going unnoticed. A victory here for Labour would be a major symbolic blow for May's leadership.

The Conservatives currently hold 39 of the 60 seats on offer. Labour has 19.

Westminster

Westminster, London. Oli Scarff/Getty Images

The state of play is very similar four miles west from Wandsworth in the borough of Westminster. Labour has never controlled this council. However, the party is hoping to pull off a historic victory, backed by a tide of disillusioned Remain voters and locals who feel let down by the government's response to the Grenfell Tower tragedy.

The Tories currently hold 75% of seats in this council. This means Labour will need a bigger swing here than it does in Wandsworth to take control of the council. A YouGov poll published last week suggested May will just about hold on to both Wandsworth and Westminster. Questions will undoubtedly be asked about her leadership if that turns out not to be the case.

The Conservatives currently hold 45 of the 60 seats on offer. Labour controls 15.

Barnet

Barnet, London. Shutterstock.com

Completing the trio of major London battlegrounds is Barnet, north London. Unlike in Westminster and Wandsworth, Corbyn would only need a slight swing in his favour to prise this borough from May's hands. That's because the Tories have just one more council seat than Labour here. The growth in popularity of Labour in the capital suggests this Conservative borough is the most at risk of changing hands.

However, while Barnet looks promising for Labour, one key determining factor could be the recent anti-semitism scandal which has engulfed the Labour Party. Around 15% of Barnet's residents are Jewish and while early predictions pointed to a Labour victory in this borough, the damage done to the party's reputation among north London's Jewish community could cost Corbyn what was once regarded as an almost certain victory. May will wake up a happy woman on Friday morning if she's able to keep Barnet blue.

The Conservatives currently hold 31 of the 63 seats on offer. Labour controls 30.

Trafford

Trafford, Greater Manchester. Shuttershock.com

We now leave the capital and divert our focus to the north-west. The Mancunian borough of Trafford is one of the key battlegrounds in this latest round of local elections. Labour generally dominates the north west of England but Trafford council has long remained a rare Conservative outpost in this area of the country. A Tory loss here would be a symbolic blow for May's party, which has made much in recent years of their attempts to win over northern voters.

The Tories have governed in Trafford since 2004 but currently hold a very slim lead over Labour. May's party would only have to lose two seats to lose overall control of this 63-seat council. That's why some heavyweight figures have visited the north-west in recent weeks. Corbyn launched his party's local elections campaign in Stretford – an area of Trafford — while the prime minister dropped in on a school in nearby Sale earlier this week.

The Conservatives currently hold 33 of the 63 seats on offer. Labour controls 26.

The south east

Tunbridge Wells, Cambridgeshire. Shuttershock.com

In the south east of England, where the Conservatives have historically been the dominant political force, recent local authority and by-election results suggest that disgruntled Remain voters are ditching the party in favour of Labour and the Liberal Democrats. Given the nature of the Conservative's dominance in the region, a drop in support is unlikely to result in councils changing hands outright today. However, a significant fall in vote share will come as a warning sign to May that her handling of Brexit is costing the party with pro-EU Tory voters. Councils to look out for here include Elmbridge, Tunbridge Wells, and South Cambridgeshire.

The Conservatives currently hold the most seats in South Cambridgeshire, Tunbridge Wells and Elmbridge. The Liberal Democrats are second place in all three.

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