The 26-year-old Bulgarian, who is studying for a PHD in social policy at Warwick University, spent Christmas 2006 with a family in Cornwall thanks to HOST.

The charity arranges short visits to the UK for students from abroad to allow them to gain insight into the country they will be studying.

Miss Kremakova said: "I thought that running from one castle to another for the first time is a very similar experience to that of an international student taking part in a HOST visit.

"You pack your things, make sure you look cheery, muster all your courage and leave your own fortress-home to crash in other people's fortresses."

Miss Kremakova, who has set a fundraising goal of £500, explained how she expected the challenge to be as enjoyable as her experience of visiting England for the first time.

She said: "You learn things about British people, the countryside and yourself. It is a once in a lifetime experience.

"Whether everything goes well or something goes wrong I am sure I will remember the day and smile all the time."

As part of her training, Miss Kremakova has been jogging around Kenilworth, swimming, doing aerobic exercises and learning Aikido.

Miss Kremakova said: "I've been tempted to stay at home over a cup of tea or go out with friends far more often than I'd like to admit. I've also had a lot of work at the university. But I know that it's only too easy to find excuses, so I just remember that I am not doing it only for myself - so I go out and run. I take each run as a little victory."

www.justgiving/milenakremakova

The Two Castles Run, which takes place on Sunday, has been organised by Kenilworth Rotary Club which has been supported by Leamington Cycling and Athletics Club.

The 10km race begins at Warwick Castle and finishes at Kenilworth Castle and will be run by 2,500 people.

This is the 26th time the race has been held and last year the event made more than £50,000 for charity.