It is believed that an alleged break-in at the Houses of Parliament last night centred on the suite of offices used by Labour leader Ed Miliband.
Scotland Yard refused to confirm the reports, but it is understood that a member of Mr Miliband's staff found that a door had been forced in the Norman Shaw buildings.
The incident is not thought to have involved the specific room that Mr Miliband uses as his personal office.
It is not clear whether anything had been taken.
More top news
Four men have been jailed for their part in the murder of a legal administrator, who was stabbed outside a pub on Borough High Street.
An American man has been sentenced to life in prison after travelling to the UK in a bid to murder a woman he met through online gaming.
The National Lottery has revealed the place where people win more big payouts than anywhere else - and it's in the capital