The number of "houses in multiple occupation" (HMOs) is thought to have risen as workers from the expanded European Union have come into the area in search of jobs and accommodation.

The city council's housing enforcement officer, Peter Bezant said: "That has made a material change, but there has also been a change in the Government definition of an HMO which has increased the numbers.

"By virtue of the fact that people in HMOs can have little day-to-day involvement with each other, fire is the greatest risk.

"Someone can be cooking in the kitchen and get distracted and leave something on, while other people in the house are sleeping after working long hours.

"When fire breaks out, they need an alarm system to give them early warning."

Mr Bezant was speaking after a case at Peterborough Magistrates' Court which saw a partner in a lettings agency fined £6,000 for managing an HMO without the correct paperwork.

Mohammed Halani, of Centre Point Letting, based in Lincoln Road, should have had a licence for a semi-detached house in Burmer Road, New England, Peterborough, as it passed the threshold of containing three or more people forming two or more households.

In fact, the property was found to be home to seven Lithuanians living as four households when Mr Bezant visited it in January after a tip-off.

The residents were living in the three upstairs bedrooms and a converted living room and had to share the solitary bathroom. Although cramped, the house was otherwise in good order.

The court heard on Thursday that Halani, who pleaded guilty to a breach of the Housing Act 2004, had thought only one family was occupying the house.

In addition to the fine, he was ordered to pay costs of £186 and a victim surcharge of £15.

Mr Bezant said 110 HMOs were currently licensed in Peterborough, with another 150 applications being processed.

But it was thought there may be 1,000 in the city, the vast majority of which need to be licensed.

Mr Bezant said: "We are very pleased with the level of fine achieved in this case.

"It is very important that landlords and managing agents operating in the city are aware of their responsibilities and of the penalties if they do not comply."

In February, The Evening Telegraph reported a small house in Gladstone Street, Millfield, was closed down by council officers after they found 13 people living in it in dangerously cramped conditions.

n If you know of a property in your area which may be overcrowded, used as an HMO, or is just in poor condition, call the housing enforcement team on 01733 747474.