Organisers of the Norfolk and Norwich Festival have insisted that future funding will not be derailed by the loss of its key sponsor next year.

Since 2004 the festival has received continued support from train operator National Express East Anglia (NXEA).

The deal, which has helped boost the reach of the audience using marketing and advertising at train stations across the region, was part of a long association with train operators in the East of England over the last 20 years, including before that NXEA's predecessors Anglia Railways and initially British Rail.

As the Festival's principal sponsor, NXEA has provided significant support for the Festival and underpinned its expansion into an event which is now recognised and anticipated not just locally, but now nationally and internationally.

But when the government stripped the firm of its franchise there were fears that the rail link would be broken.

The changeover comes as festival bosses said they were thrilled with the audience response this year, which had seen record numbers at events like Saxophone Massive, Deabru Baltzak's incredible The Wolves and the weekend of free outdoor street theatre, which brought thousands of people to the city and Chapelfield Gardens.

The three bidders shortlisted for the new Greater Anglia franchise, which will start on February 5, 2012 and run for 17 months, with an option to extend by up to one year are the Go-Ahead Group, Stagecoach, and Dutch rail firm Nederlandse Spoorwagen.

However the team behind the festival said they had factored the impending funding change into their planning for next year, and while it was still too early to say what would happen there were plans to speak to the successor firm when they are appointed in November.

William Galinsky, Artistic Director of Norfolk & Norwich Festival, said: 'National Express East Anglia has been an amazing support to the festival. They've really helped us get to where we are today, but we do have a long history of working with the train operator in the region - whether that's NXEA or another operator. Transport remains a major part of getting to and from the city so I'll be optimistic that we'll continue to work with a rail operator in the future'.

Mr Galinsky also paid tribute to the festival's principal funders including the Arts Council of England, Norfolk County Council and Norwich City Council and NEEAnglia as well as May Gurney, which helped bring the free events to the festival.

And he said next year he would like to even more world and UK premieres to make the event a truly world class festival

'There's been plenty of sell-out shows and we've enjoyed record-breaking weeks at Norwich Theatre Royal and Spiegeltent,' he added. 'What's been wonderful to see is the real appetite for the diversity of the festival's programme, with everything from fantastic International theatre at Epic Studios to the quirky and charming Dining with Alice at Elsing Hall attracting enthusiastic responses from festival audiences.'

Jonathan Denby, head of corporate affairs at NXEA said: It's too early to judge on sponsorship arrangements for next year but whatever happens we're very proud of what we've been a part of in the last few years. Our partnership has enabled the Norfolk and Norwich Festival to go from strength to strength, becoming a fantastic annual celebration which is fun for audiences and the local community, whilst at the same time supporting the local economy and building Norfolk and Norwich's reputation'.