Tony and Cherie Blair set for £1million profit on house for son Euan in just 3 years Central London house is on the market for £2.35million The Blairs bought it for £1.29million in Cherie and Euan Blair's names in 2010 But the property is advertised as having a separate basement apartment - which Westminster Council has never given permission for They've always been pretty shrewd about playing the property market. But even by the standards of Tony and Cherie Blair, their latest transaction is set to be particularly lucrative. A four-storey house bought for £1.29million for eldest son Euan has been put on the market for £2.35million - leaving the Blairs with a potential £1million profit in just three years. There's one snag, however. The house is being marketed as containing a "separate apartment," even though planning permission has never been obtained for one. The Central London home was bought in the name of Euan, 29, and his mother Cherie in 2010. It immediately attracted controversy because of an attempt to get planning permission to separate the basement into a self-contained flat. Westminster Council received an application to build steps down to the basement from the street, and to divide it into a separate flat. The internal stairs to the basement were to be removed. Three neighbours complained, fearing greater pressure on parking, rubbish collection and other services, and after advice from the council the application was amended. On the market: The Central London property has an asking price of £2.35million This application retained the new external entrance - and its own kitchen - and was duly approved. However, a council officer noted in June 2010: "This permission does not authorise the use of the basement as a separate self-contained flat." By May 2011, the council received a complaint that Euan had replaced a door to the upper floors with a wall, in an apparent attempt to create a separate basement flat. Following "enforcement action" the council was told the wall was being replaced by a door. But last year, the battle to create a separate flat resumed and, at one stage, a new number was placed on the basement door, along with a letter box. The council again took "enforcement action" saying that it received a report of "general nuisance (loss of amenity) ," involving the "use of the basement as a self-contained flat." Visits from the council led to a denial from Euan that he was using his basement as a separate flat, and the action ceased. But the property is now being marketed by Sandfords estate agents as having "a separate apartment on the lower ground floor" ideal for a "separate office or rental investment." There is no warning it still needs planning permission. Last night sources at the estate agents claimed that the one-bedroom flat had been rented out for £1,200 a month. The source said a locked door on the stairs to the upper floors ensured the basement could be used as a separate home. Last night a spokesman for the Blairs refused to explain why both the house advert and estate agent suggested the basement was a self-contained home - but insisted Euan and Cherie had done nothing wrong. "Westminster Council has already accepted that there are two units, which is why it charges two separate council taxes," the spokesman added. A spokesman for Westminster Council said: "No planning application has been received to divide this house into two dwellings - and following information received we have now started an investigation." Another council spokesman said council tax valuations had no bearing on whether planning permission had been issued for the basement flat to be a separate dwelling. Last month Euan married girlfriend Suzanne Ashman, 25.