The borough's RSPCA is once again struggling with financial woes, now that its main fundraising event of the year has been cancelled.
Each year the Hillingdon, Slough, Windsor, Kingston and District RSPCA branch, which has a clinic in Uxbridge Road, Hillingdon, holds a dog show and summer fair at Pinewood Studios in Iver Heath.
But studio managers have this year told the RSPCA they can no longer afford to cater for charities.
Irene Hansford, chairwoman of the branch, said: "We've had a real body blow. Its our major fundraising event of the year.
"What we are desperate for now is a new venue. We need somewhere with parking for about 800 cars. The day usually brings in about £8,000, which is essential to us."
The branch is trying to sell the clinic and move to a less costly site.
Nearby Crescent Parade has been cited as a possibility.
Mrs Hansford said: "We don't know if it is going to sell, but the clinic is on the market and finances mean we have to downsize.
"The service is needed now more than it has ever been. People haven't got the disposable income to spend on a pet. The charity shops are keeping us afloat.
"I really don't know what would happen if we had to shut - there are 12,000 animals that use this clinic, and [numbers have] shot up this year.
"It's full of large dogs. People don't have the money to feed them and often they have to work full time and you can't leave a big dog at home all day.
"The bad news has really knocked us. We've never needed help like we do now."
Nobody at Pinewood Studios was available for comment.
The fair used to be held at Hillingdon Council's Southlands Arts Centre in The Green, West Drayton, but because of its popularity, the venue became unsuitable.