LONDON - British Home Secretary Jacqui Smith will be quizzed for allegedly misusing 116,000 pounds (Rs14m) of her Parliamentary housing allowance while lodging with her sister. She has been asked by Parliament's anti-sleaze watchdog to justify her House of Commons expenses claims, it has been revealed. In a highly embarrassing development for a senior government minister, John Lyon, the Parliamentary watchdog, announced that he was conducting an official probe into the Home Secretary's living arrangements. Lyon had previously turned down two requests for an inquiry but he has now taken the first step towards a full investigation after a complaint from Ms Smith's neighbours. The Home Secretary has claimed at least 116,000 pounds from the Commons second-home allowance and possibly up to 200,000 pounds (Rs25m) since becoming Member Parliament. " Asif Mehmood The move follows a complaint from neighbours of Miss Smith's sister Sara, casting doubt on the claim that the London address where she lodges during the week is her "main home". By registering the 400,000 pounds house in her Midlands constituency in which her husband and children live full time as a "second home," the Home Secretary has been able to claim at least 116,000 pounds in tax payer-funded allowances. Ms Smith insisted that her claims on the public purse were entirely legitimate, saying that she was confident that she had "followed the rules" for MPs' second homes, saying "I sought advice about the arrangements that I make for living in two places like lots of MPs have to. I followed the advice that I was given and I followed the rules." "And therefore I'm very happy to answer further questions that the independent commissioner puts to me." Critics however accused Ms Smith of seeking to maximise her allowances by claiming on the family property, rather than her sister's. David Cameron, the Conservative leader, said that as well as abiding by the letter of the rules, it was important that politicians were seen to behave "responsibly" with tax payers' cash. He said: "The Home Secretary does have some questions to answer on that front." Lyon has asked Ms Smith to provide him with a detailed breakdown of how she divides her week during the Parliamentary recess as well as when the Commons is sitting. When her arrangements first came to light earlier this month, the watchdog initially dismissed two complaints against Ms Smith on the grounds that the allowances had been cleared by the House authorities. He has decided to launch an inquiry now after receiving a third complaint, this time from Dominic and Jessica Taplin, who live a few doors down from the Smith sisters. They claimed in a Sunday newspaper that the Home Secretary often stayed at the London address for just two days a week. Mrs Taplin said: "When I read that she says she spends most of the week here I thought: 'That is a fabrication'." Her husband added: "You can tell when she is here because the police guards arrive first. They turn up mid-morning on Monday and leave mid-morning on Thursday." Lyon has asked the Home Secretary to clarify exactly how much time she spends in London. Sources close to Ms Smith rejected the Taplin's claims, saying that the police presence would not always be obvious to her neighbours. The source added: "Their allegations are completely unfounded. The police will confirm that their protection of the Home Secretary does not necessarily mean posting officers directly outside her house. "Sometimes they can keep an eye on her much more discreetly, so these neighbours really don't know what they're talking about. "She spent the Christmas period in London - which shows that she considers that address her main home - she's also here now during the Parliamentary recess. "Being Home Secretary is a full time job, and she needs to be in London as much as possible."