A plan to give out free croissants to travellers urging them to remain in the EU has been banned by the elections watchdog.

But commuters at London's King's Cross and St Pancras stations were allowed to be given postcards from Parisians asking them to stay in the EU.

The Electoral Commission said that #operationcroissant, the plan to give out 600 croissants at King's Cross St Pancras, was prohibited under "treating" rules.

Its guidelines state: "A person is guilty of treating if either before, during or after a referendum they directly or indirectly give or provide any food, drink, entertainment or provision to corruptly influence any voter to vote or refrain from voting. Treating requires a corrupt intent - it does not apply to ordinary hospitality."

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Instead, the 600 croissants which came from Paris on the first Eurostar of the day were donated to homeless shelters.

Postcards asking Britons to stay in the EU were given out as planned.

Messages ranged from the meaningful (Let us keep together to fight for human rights, such as freedom of movement and freedom of speech) to the funny (There are not enough croissants in France to express how much we love you guys!).

Rosa Rankin-Gee, a writer based in Paris, came up with the idea when a British friend said she was not sure which way to vote in the referendum.

The friend sent a photo of her postal vote along with a promise to vote remain if Ms Rankin-Gee bought her a croissant from Paris.

The plan grew from there, with a whole team working on bringing croissants to 600 people the day before the historic vote on whether Britain should stay in the European Union.

Before the Electoral Commission stepped in, Ms Rankin-Gee said #operationcroissant was not a political statement: "We are avoiding messages which ask you to vote a certain way. We all are aware of the vitriolic nature of the campaign, and we really want to do something that is stripped of the angry, politicised and divisive campaigning.

"We wanted to do something sweeter."

However, that did not stop the police from getting involved, and contacting the team to let them know they could be breaking the law.

Team Operation Croissant said in a statement: "It was never our aim to buy votes... it was conceived as an act of friendship, proximity and goodwill; an act of breaking bread.

"We are happy to fall on our baguettes and stick to the right side of British law."