British PM Boris Johnson has been accused of stealing an opposition Labour MP’s idea after releasing an ad parodying romantic comedy Love, Actually.

Mr Johnson’s Conservatives flooded social media on Tuesday with an ad parodying from the 2003 movie about the love lives of assorted Londoners over the holiday season.

It shows Mark (Andrew Lincoln) standing at the door of secret crush Juliet (Keira Knightley), professing his love for her on cue cards, while her new husband sits obliviously inside.

In the ad, Mr Johnson stands on the threshold of a elector’s home, promising that if she votes Conservative “by this time next year, we’ll have Brexit done … and we can move on”. The ad ends with an entreaty to “Vote Conservative actually”.

It came as British voters get set to head to the polls on Thursday (Australian time) for the country’s all-important election.

Mr Johnson has said he will lead Britain out of the European Union by January 31 if he wins.

But opposition Labour candidate Rosena Allin-Khan accused the Conservatives of ripping off her own similar Love, Actually spoof, posted several weeks ago, in which she persuades a Conservative voter to change his mind.

Within minutes of Mr Johnson’s ad being posted online, Dr Allin-Khan responded:

“Try not to retweet Boris Johnson’s copycat version of #ElectionActually – it’s what he wants you to do,” she wrote.

“Instead, help share my original version.”

I won't be retweeting it – but Boris Johnson has copied my #ElectionActually video.

Tanks. On. The. Lawn.

Don't share his version in outrage – instead, share my original version.

It's us versus Cummings, Johnson, Trump and Farage – retweet this and spread the word! pic.twitter.com/vuC26bWlcy

— Dr Rosena Allin-Khan (@DrRosena) December 9, 2019

The Conservative ad also sparked a flood of parodies, with rival parties and social media users replacing the writing on Mr Johnson’s cards with less flattering slogans.

Former justice secretary David Gauke, who was expelled by Mr Johnson for opposing his Brexit plan and is running as an independent, tweeted a photo of himself holding a card with the words “Brexit won’t get done, actually”.

One of Love, Actually‘s stars is Hugh Grant, who plays a boyish British PM who berates a boorish US president played by Billy Bob Thornton.

During the British election campaign, Grant has been out on the campaign trail with non-Conservative candidates, urging electors to vote tactically to kick Mr Johnson’s party out of office.

Hugh Grant is pulling a ‘Love Actually’ move and going door to door asking British citizens to vote against Boris Johnson pic.twitter.com/vwoYt5Djj3

— NowThis (@nowthisnews) December 5, 2019

“I did notice that one of the cards from the original film that he (Johnson) didn’t hold up is the one where Andrew Lincoln held up a card saying ‘because of Christmas you tell the truth’,” Grant told the BBC.

“I just wonder if the spin doctors in the Tory party thought that was a card that wouldn’t look too great in Boris Johnson’s hands.”

-with AAP