Almost half of landlords have increased rents in the 12-month period to September 2011, says BDRC Continental. Photograph: Graeme Robertson/Getty Images Rents rose in the month of January for the first time in four years because of an unusually high number of tenants looking for a limited number of properties, according to latest data. The news is in stark contrast to David Cameron's assertion in parliament last month that private rents are coming down thanks to housing benefit reforms. Cameron's claim has already been disputed by housing sector professionals, including the Chartered Institute of Housing and the National Landlords Association. In January 2012, the average rent in England and Wales increased by 0.1% to £712 a month, equating to an annual rise of £30, according to LSL Property Services, which owns the UK's largest lettings agent network. While acknowledging this was a small rise, it said it was the first time since it began compiling the index in 2008 that rents rose on a monthly basis in January, and was the first monthly rise in three months. David Newnes, director of LSL Property Services, said lettings agents had already seen a higher than normal level of competition for properties over the Christmas period, and that this activity had not abated. "The rental market burst back into life unseasonably early in January, with tenants on the move trying to take advantage of what is usually a quieter period for the rental market," he said. Mortgage lending has shown signs of improving in recent months, but transactions remain at almost half their historic levels and the increasing dependency on rental accommodation will drive further rent rises over the long term. Rents rose fastest on a monthly basis in the West Midlands and the south-west, where they increased by 1.8% and 1.5% respectively last month. Rents rose by 0.8% in London, where they have only fallen once in the past 13 months. However, rents fell in four regions, with the biggest declines in the east of England and Wales where they fell 1.7% and 1.5%, LSL said. Despite the fact rents are rising, many landlords are feeling the pinch, according to separate research from market research agency BDRC Continental. It found that in the fourth quarter of 2011 the number of "portfolio landlords" - those with 20 or more properties - who reported making a loss rose from 1% in the third quarter of 2011 to 8% in the last quarter. It added that despite almost half (46%) of landlords having increased rents in the 12-month period to September 2011, the last quarter of last year saw rental yields for all landlords fall to their lowest level in the year. David Whittaker, managing director of Mortgages Business, said of the BDRC findings: "Professional landlords are in a better position than many others in the property sector, but rising rents and stagnant property prices don't necessarily mean landlords are hovering over a barrel of fish with a 12 gauge shotgun. Like any other investor, landlords must select their investments wisely and choose the types of property that are going to give them the best returns. Rental arrears also remained high in January, according to LSL, with 10.7% of all rent late or unpaid at the end of the month. This was largely unchanged from December 2011 but above the average of 10.2% for the previous 12 months.