Landlords have been warned of a sharp rise in sub-letting scams as sky-high demand for property gives unscrupulous tenants the opportunity to bend the rules.

Patterson Bowe, a lettings and sales specialist of Kensington and Chelsea, said a growing number of landlords have discovered their properties had been illegally sub-let without their knowledge or consent.

Managing director Stuart Patterson said: “Undersupply and increased demand in the current market has left room for certain tenants to bend the rules where they can.

“We have been contacted by both landlords and tenants looking for advice because they have fallen victim to these scams, particularly illegally sub-letting property throughout prime central London.

“Often these are short-term tenants who are here from overseas and searching online for temporary accommodation without appropriate knowledge or advice.”

Patterson urged all landlords to carry out rigorous due diligence and formal background checks on tenants before signing contracts.

New research from Rentify shows that extortionate fees are the most common complaint landlords make about letting agents.

Almost three quarters of 500 British landlords felt letting agents’ fees were too high, with almost half also experiencing poor customer service.

​Other concerns raised by the landlords surveyed referenced ‘poor customer service’, with 33% of respondents saying they struggle with some agents’ 9-5 working hours. 

Insufficient tenant referencing and inaccurate property valuations were also cited as problems by over 20% of participants.