Weather forecasters expect a polar vortex from the Arctic to send temperatures plummeting in the next few weeks.
And pest experts fear a combination of icy conditions and overflowing dustbins could lead to a huge spike in the number of unwanted visitors during the holiday period.
Dee Ward-Thompson, of the British Pest Control Association, believes the double attraction of food and warmth has the potential for problems.
She said: “We have had abnormally mild conditions throughout the UK this year and that is likely to have led to an increase in the number of rats. Any cold snaps on the way will drive them into buildings in search of shelter and they’ll also go scrounging for food from bins and bird tables. So the Christmas and New Year period is likely to provide the perfect opportunity, particularly as it’s party time with fewer bin collections.”
A typical home may have more than a dozen potential entry points for rats, which can transmit a variety of diseases to humans. They get through gaps as small as 2cm, often using and unscreened vents or gaps in the eaves and roof edges.
Mrs Ward-Thompson added: “The first evidence of rats in a home is often noises under the floor, in the walls or loft as that’s where most will head to once they’re inside. Quite apart from the health risks, they’ll foul water tanks and chew on wood or electrical wires which can cause a lot of damage and poses a fire hazard.”