A police crackdown is being launched tomorrow on 'charity' con artists targeting Oxford city centre.

The warning is going out to both tourists and locals who run the risk of falling victim to illegal charity collectors taking money from unsuspecting members of the public.

Thames Valley Police are also taking action over an increase in the number of mobile phones and other valuables being stolen from cafes and shops.

Today officers will be giving out fliers and putting up posters in cafés and other stores to raise awareness about scams.

Pc Vikki Barrie said: "This has been a problem in recent months and while we are making arrests and charging people, we have to make sure they are not tolerated by the public. We are warning people to be wary of collectors - including women and children - particularly those carrying clipboards and claiming to be collecting for the hard of hearing."

She added: "Make sure you check charity workers' ID, look for a registered charity number, and only donate money when you are confident they are from a legitimate organisation."

Oxford University students and a representative of Costa Coffee, who have fallen victim to fraudulent con artists, will join the police to help raise awareness by talking about their experiences.

Oxford City Council's tourism co-ordinator Susan Lockhart will also be on hand to offer advice.