Image caption Since changing the account name Mr Johnson has tweeted from the mayoral campaign trail

Labour have made an official complaint after Boris Johnson transferred the Mayor of London Twitter account into his name.

The accountnow links to the Back Boris 2012 website instead of the City Hall website, www.london.gov.uk, as before.

The move - on the first official day of the mayoral election campaign - means the account's 253,000 followers have also migrated to Mr Johnson.

Mr Johnson's campaign said those who wished to could 'unfollow' the account.

The vote for London mayor will be held on 3 May.

'Hijack'

On Tuesday, Conservative incumbent Mr Johnson tweeted: "Day 1 of official election period! No City Hall resources in use, so all Tweets until 3 May are from my phone or @BackBoris2012 team."

He has since written about campaigning in the London borough of Bexley.

But the decision to transfer the account has provoked criticism on Twitter, including from fellow candidate for mayor Liberal Democrat Brian Paddick.

He wrote: "Is Boris Johnson so inept at drumming up support he needs to hijack @MayorOfLondon? Cheap trick, #handitbackboris."

Rest assured that the account is still - and has always been - controlled by Boris Statement, Back Boris 2012 campaign

Labour Party London Assembly member Len Duvall has written to Ed Williams, monitoring officer for the Greater London Authority's Standards Committee, to complain.

"My understanding is that this Twitter account was established by the Authority and belongs to the Office of the Mayor of London, and has been maintained since its inception by GLA resources," he wrote.

"As such, this account does not belong to the current Mayor of London, Boris Johnson. Can you quickly establish the facts and intervene on this abuse and misuse of resources in undertaking this transfer.

"If it is found this is a personal account, it has featured on a number of GLA and mayoral publications and I would expect the organisation to be reimbursed the full sum that have been spent on this personal and political campaigning."

A GLA spokesperson said: "Boris Johnson has decided it would not be appropriate during the pre-election period for him to be tweeting as Mayor of London.

"He has therefore made it clear to all his followers that he will now be tweeting under his own name outside of City Hall.

"Anyone who no longer wishes to follow his tweets will be reminded repeatedly that they can unsubscribe with one click of the mouse.

"@mayoroflondon can be revived by whoever is elected on May 3."

Ownership

A spokeswoman for the Electoral Commission said there were no specific rules relating to the re-branding of Twitter accounts or the inheritance of followers.

But she said any money spent on the account from now on would have to be published in Mr Johnson's campaign expenses.

The question is who owns the account Mark Dennis, Intellectual property lawyer

Mark Dennis, intellectual property lawyer at Taylor Wessing, told the BBC: "The question is who owns the account.

"If Boris Johnson was posting the tweets himself, as appears to have been the case, he may have a good argument that it is his own private account.

"Alternatively, if the feed was operated and resourced by City Hall employees, there may be a case to argue against this."

Asked whether Mr Johnson had personally written all the tweets published under the @MayorOfLondon name, a GLA spokeswoman said: "It's the authentic voice of the mayor. That's what we say."

In 2009, Mr Johnson was given guidance by the GLA after a member of the public complained about a tweet sent from the mayor's account celebrating the Sun newspaper's decision to back the Conservatives for the forthcoming general election.

In deciding the complaint, the GLA said it was "not clear" whether or not the tweet was written by him, but said it was "clear that it was written by or on behalf of the Mayor of London, as the hyperlink to the Twitter account was found on the Mayor of London page on the GLA website".

In respect of all acts complained about, Mr Johnson, the Mayor of London, was clearly acting in his official capacity, and was therefore required to comply with the GLA's Code of Conduct," it added.