Voting is under way in a host of elections across the UK, with party leaders joining millions of people in casting their ballots to select their local representatives.

Council seats are up for grabs in Scotland, Wales, London and many parts of England, while Northern Ireland is electing its new Assembly.

Boris Johnson arrived at a polling station in Westminster on foot early on Thursday morning, appearing in good spirits despite predictions that the Conservatives could lose hundreds of council seats.

The Prime Minister, showing his party colours with a light blue tie and shirt, waved to reporters on his way in and out of Methodist Central Hall.

One member of the public looked perplexed at the commotion, wondering aloud: “Is that Simon Cowell?”

Mr Johnson was not with his wife Carrie but was accompanied by their dog Dilyn, taking part in a tradition of recent years of people taking their pets with them when they vote.

The excited Jack Russell cross leapt up and licked a photographer attempting to get a shot of the Prime Minister.

Social media users have been sharing photos of their dogs at polling stations across the UK since they opened at 7am.

After voting, Mr Johnson tweeted a video in which he said he voted for his party because “it’s Conservatives who deliver, Conservatives who get the bins collected”.

Sir Keir Starmer held hands with his wife Victoria as he arrived at a polling station in Kentish Town, north London, to cast his vote in the local elections for Camden Council.

The Labour leader tweeted afterwards: “Today is our chance to send the Tories a message they can’t ignore: Britain deserves better”.

Sir Ed Davey, casting his vote at Surbiton Methodist Church in south-west London, said the Conservatives will be punished in the local elections for their handling of the cost-of-living crisis.

Wearing a lapel badge of the Union and Ukrainian flags, the Liberal Democrat leader arrived on foot, having made the walk from his constituency office where he passed a hearse with its back door open.

The Lib Dems are hopeful of causing an upset in Hull by dislodging it from Labour’s control, while also vying for victory against the Tories in places such as Wokingham and Sutton.

The Kingston and Surbiton MP said while taking Hull City Council could be a “problem” because “it’s in the north and it’s against Labour”, there is still a possibility of doing so, joking: “We have an affinity with Kingston-Upon-Hull, we’re in Kingston-Upon-Thames.”

Scottish First Minister Nicola Sturgeon made the case to vote for the SNP at her local polling station in Glasgow, while her Welsh counterpart Mark Drakeford wore a red tie for Labour as he cast his ballot in Cardiff.

The Conservatives will find out in the coming days as votes are tallied whether they will be made to pay the price for the so-called partygate saga in Downing Street, which has seen Mr Johnson and Chancellor Rishi Sunak fined for breaking coronavirus laws.

A former Conservative minister revealed that he voted Labour for the first time since Tony Blair’s 1997 general election landslide.

Nick Boles, a former MP for Grantham and Stamford who left the Conservative Party in 2019, tweeted: “First time I’ve voted Labour since an equally glorious May morning in 1997.”

Tory supporters are likely to anxiously be watching out for results in true-blue London local authorities such as Wandsworth – under Conservative control for the past 44 years, Westminster and Barnet, where pollsters YouGov believe Labour could cause an upset.

As well as partygate, the Tories have been hit with a string of other controversies, including former Wakefield MP Imran Ahmad Khan being found guilty of sexually assaulting a teenage boy and veteran MP Neil Parish quitting after admitting he watched pornography in the Commons.

Meanwhile, there have been Tory calls for Durham Police to look into whether Sir Keir broke Covid rules while campaigning before the 2021 Hartlepool by-election.

But the Labour leader claims it is a “smear” to suggest he breached the regulations while having “a takeaway and a beer while I was working late at night”.

In England, more than 4,000 councillors in 146 councils are standing for election in major cities including Leeds, Manchester, Birmingham and all 32 London boroughs.

All 32 councils in Scotland and all 22 in Wales are also holding elections, with polls open between 7am and 10pm.

Meanwhile, tensions are high in Northern Ireland for the Stormont election, where voters are going to the polls across 18 constituencies to elect 90 MLAs.

Opinion polls have suggested Sinn Fein is likely to top the poll, while the Alliance Party is tipped to see a surge in support.