A plucky sparrow that has evaded capture in a Watford supermarket for the past week is likely to remain in the store for more than a fortnight, it has been revealed.

Customers and staff at Tesco Extra, in Lower High Street, spotted the bird, which is a protected species in the UK, flying around in the shop's rafters early last week.

Because of its status, management were forced to seek approval from environmental organisation Natural England before being allowed to catch the unwelcome customer - a process which could take up to a fortnight.

Tesco spokesperson Rory Stoves said: "The staff will do what they can until they get the licence but, because it is an environmental species, they are restricted to keeping the doors open and hoping it flies out.

"It has happened in a couple of our other stores across the country - there was one in Norwich that evaded capture for more than a month."

Mr Stoves also confirmed that the store has received no complaints about the animal.

The RSPCA did receive one phone call from a concerned customer, who said they had spotted a pigeon in the store, though Tesco confirmed the animal is a sparrow.

RSPCA spokesperson Kalie Rydings said: "We do not have tools to carry out a rescue of the bird and we would not want to distress it further."

Despite flying around the shop, which is open 24-hours a day, Mr Stoves said the sparrow did not pose any health risks to customers or to the produce.

He said: "We have been told there are no health and safety concerns. Being a 24-hour store, there is always activity so, although it occasionally flies down and lands on display cabinet, it mostly just hangs around in the rafters.

"We are very strict on cleanliness so if it does cause any mess it will be dealt with quickly. It is just the one bird and is not a big problem at the store."