The poster says Natasha looks much younger than her 15 years

Diane Cousins, 55, took the desperate measures following the disappearance of their 15-year-old Labrador-cross.

She even persuaded her husband Roy to contribute money left by his father.

Natasha, who is tan-coloured, went missing in March when workmen apparently left a door open at their home in Bromley, south-east London.

Mrs Cousins, who also cashed in her engagement ring, told BBC News: "It may be only a dog to you but it's my life. Natasha is so much part of my life.

You cannot turn a page and say goodbye to a dog because someone has stolen it Diane Cousins

"I would do anything to get her back and by offering this reward I hope I do get her back.

"She has been with me for nearly 15 years and you cannot turn a page and say goodbye to a dog because someone has stolen it."

She said she has put up posters of Natasha all around her neighbourhood but has had no response so far - despite the reward.

"My husband and I have not stopped looking for her and we won't stop looking for her," she added.

'Small price to pay'

Mr Cousins, a builder, said: "In the long term it's going to be a small price to pay.

"My life has been turned upside down since the dog went missing. Diane has been going wild.

"We're exhausted. I just want to get my life back to the way it was rather than spending 24 hours a day, seven days a week looking for Natasha."

Mrs Cousins, a receptionist, said she fears her elderly pet who needs regular veterinary attention, may have been stolen.