The man, in his 50s, was working at a contact lenses warehouse in Segensworth, near Fareham, when an adder was found in the building. He tried to remove it but was bitten on the hand in the process.

An ambulance was called to the CooperVision warehouse in Concorde Way.

The man was treated at the scene by paramedics and then taken to Queen Alexandra Hospital, Cosham, for further assessment after being bitten, last Thursday.

Laura Zobel, a spokeswoman for the company, said: 'CooperVision is pleased to say that the member of staff is recovering well.'

Adders, which can be recognised by the dark zig-zag along their backs and dark coloured V marking on their head, are the UK's only venomous snakes. They live in undergrowth and are known to come out in warm weather to bask in the sun.

RSPCA spokeswoman Jo Barr said: 'It's not unusual for people to see adders in the warmer months. It's a bit more unusual for them to go into buildings but it's possible this one was looking for cover and shade.

'People shouldn't try and pick adders up.'