Swarms of flies plagued walkers on Worthing seafront yesterday, thanks to the mild winter weather.

Millions of seaweed flies - Coelopa frigida - flew around the Pavilion Theatre, Worthing, where people eating their lunch had to continually swat them away.

Rowland Furse, an entomologist with East Grinstead-based Rentokil Initial, said: "There are about 100,000 species of fly worldwide and thousands native to this country.

"These sound as if they were probably seaweed flies. They are not known for carrying diseases like houseflies or bluebottles but can be a nuisance because there are large numbers where you don't want them.

"It is extremely early in the year to be finding them. They tend to move faster and breed more quickly when it is warmer in the summer.

"But we have had a relatively mild winter and I have seen a couple of bumblebees already, which is very early."

Argus weather expert Ken Woodhams said: "We have had a mild spell and it has been 10C (50F) or more every day since January 20.

"That is six to eight degrees Farenheit above normal for February."

Worthing foreshore inspector Ian Miller said: "It takes a spot of sunshine and a few hours of warmth and it brings the flies out.

"It has been very mild the last day or two which would account for it. Having said that, I have not encountered them yet."

The flies only live for a few days.