The princess pulled out, but the show went on, at former RAF Coltishall where the final countdown has begun to a new era of hoped-for prosperity in its proud history.

On April 1 the one-time Battle of Britain base, now Scottow Enterprise Park, will gain official Enterprise Zone status.

In what had been planned as a royal visit, VIPs toured part of the 26 hectare site without Princess Anne, who cancelled her plans at the last minute due to illness. She will come in the autumn instead.

Other guests met some of the 38 tenants on the Norfolk County Council-owned site and heard about an expected flood of interest after April 1, bringing scores of new jobs to north Norfolk.

At least another 27 businesses and 268 jobs are expected on the park over the next five years, with some successful tenants creating hundreds more jobs nationwide.

Firms will benefit from Enterprise Zone perks including a business rates holiday of up to five years, access to superfast Broadband and simplified planning rules.

Simon Coward, managing director of Hethel Innovation, who is offering expert advice at Scottow, said April 1 would also mark the date when the final phase of the Scottow Moor Solar park, one of the largest in the country, was completed on the site.

It is one of a number of pioneering businesses with a focus on renewable energy and sustainable building techniques which are converging on Scottow.

At least five new engineering firms would be joining them next month, according to Mr Coward.

One new arrival is Beattie Passive, which makes cheaper, quicker-to-build eco homes with 90pc less heating needed than conventional houses.

Ron Beattie said his firm would create about 20 jobs to start with, but one potential client wanted 400 homes built.

'It's a phenomenal opportunity for employment in north Norfolk,' he added.

John Gunn, of innovative home-building firm Tufeco, said it would also create about 20 jobs initially. But there was huge interest in the company's technique of turning recycled glass into tiny beads which could be formed into panels to build affordable homes.

'Over the next year I would expect hundreds of jobs to be created by Tufeco,' said Mr Gunn. 'We have work coming out of our ears across the UK.'

VIPs also met Neil Gray who hopes to turn the former base's gym into Runways, a community playbarn, with facilities for children from birth to 12, party rooms, plus separate space for teenagers.

Mark Goodall, board member of the New Anglia Local Enterprise Partnership, said the Northern Distributor Road, due to be finished early in 2018, would greatly improve access to north Norfolk.

When Scottow Enterprise Park was RAF Coltishall it had: 'played a crucial role in our defence from the Second World War right up until its closure 10 years ago,' said Mr Goodall. 'Now it can play a crucial economic one.'

Rex Parkinson-Hare, chairman of Norfolk County Council which paid £4.1m for the airbase three years ago, said the tour had been an eye-opener.

'It was a huge site, with colossal potential, going, to my mind, at a very reasonable price,' said Mr Parkinson-Hare.

'I think it was a very good move by the county to buy it. 'Their foresight is going to be rewarded by businesses coming here and bringing jobs to Norfolk, which is what we need.'