Sandringham: 1,000s expected for Robbie Williams, The Who and Van Morrison gigs

Tickets for the Robbie Williams concerts sold out as soon as they were released last year

Tens of thousands of music fans are to descend on the Sandringham royal estate for four days of gigs over the bank holiday weekend.

Van Morrison kicks off proceedings on Friday night, with Robbie Williams headlining on Saturday and Sunday, followed by The Who on Monday.

Organisers said they were expecting up to 20,000 fans each night.

Norfolk Police warned that roads were expected to be extremely busy in the King's Lynn/Hunstanton area.

The estate, where the Royal Family usually gathers for Christmas, has staged concerts before, such as Will Young in 2010, but with much smaller audiences.

This weekend's concerts have been organised by Heritage Live, and promoter Giles Cooper said they were "the biggest events that have ever happened at Sandringham".

"We're expecting about 20,000 people per night - especially on the Robbie Williams nights," he told BBC Radio Norfolk.

"It's about an experience for people... where they can see some of their favourite music in the most idyllic and outstanding location."

Support acts over the four nights include Squeeze, Del Amitri, Richard Ashcroft and the Lightning Seeds.

An extra date for the Angels singer was added to the gig roster on the royal parklands

Mr Cooper said tickets for the two Robbie Williams shows sold out within one day when they went on sale in November.

"On the same afternoon every hotel, B&B, campsite in the area instantly sold out of their rooms... and whilst it's difficult to gauge exactly the figure, we... estimate it's in excess of £20m that's come into the local area as a result of these concerts," he said.

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The concerts on the royal parkland are part of Williams' XXV tour, which marks 25 years since he left Take That to go solo.

Mr Cooper said the Sandringham gigs were the "last two shows of [Robbie Williams'] entire world tour".

"Same with the Who - they've been touring with an orchestra for most of the last year and it's the last day of their tour - so some very special nights."

Legendary band The Who will headline backed with an orchestra on Bank Holiday Monday

Asked about traffic management, he said it was "the nature of the beast" for stately homes such as Sandringham to be located in remote and rural areas.

"We've been working with the police, the local authorities, the highways authorities for many, many months."

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He said the views of local residents had also been "taken on board".

"We hope we've come up with the best plan we can," he added.

"I think it's worth saying that no matter how good the traffic management plan, there will be delays with 20,000 people turning up every night, that is a lot of cars, but we advise everybody to set off early and get here early as there's a lot to enjoy before the music."

Several diversions and one-way systems have been implemented to help cope with the extra traffic.

Belfast singer and musician Sir Van Morrison is known for songs such as Brown Eyed Girl and Gloria, as well as albums including Astral Weeks and Moondance