Boris Johnson today proudly tweeted saying that he had voted Conservative.
Mr Johnson, who represents Uxbridge and Hillingdon in west London, posted a message saying: "I just voted Conservative in the local elections. Make sure you do too! You’ve got two hours left to get out and vote!"
The message only stayed up for half a minute after users pointed out to the Tory MP that there were no polls in London.
But the website Politwoops, which stores deleted tweets by MPs, handily recorded the gaffe.
It is far from the first time that Mr Johnson has made such a slip up.
His colourful language has frequently got him in trouble including saying Muslim women who wear burkas look like 'letter boxes', calling black people 'picanninies' and saying that former US President was 'part-Kenyan'.
Elections took place in 248 English councils outside London, and 11 local authority areas in Northern Ireland.
There were also polls for six elected mayors in Bedford, Copeland, Leicester, Mansfield, Middlesbrough and the new North of Tyne devolved regional authority.
Local elections results times 2019: Hour-by-hour guide to declarations across UK
Close to 60% of the 8,425 seats that were in play in England were Conservative, with a quarter held by Labour .
The last time a majority of the seats were fought over in 2015, the Tories were on an electoral high as they secured their first Commons majority since 1992 on the same day.
Most of the electoral battles took place in the Tory shires or Labour strongholds in northern cities, limiting the prospects for large-scale gains by Jeremy Corbyn's party.
The results are unlikely to be a guide for European elections scheduled for later in the month, as neither Nigel Farage's Brexit Party nor the Remain-backing Change UK fielded candidates.
However, Brexit was believed to have played a major role in the elections.
Conservatives were concerned Leave-backing supporters would stay at home or switch to Ukip in anger at Mrs May's failure to deliver Brexit on time on March 29.
New International Development Secretary Rory Stewart makes play to be Prime Minister
Councils to watch include Dudley, Trafford and Derby, where Labour could gain overall control, and Swindon, Great Yarmouth, Redditch and St Albans, where control could slip out of Tory hands.
The Liberal Democrats hoped to seize Winchester.
