By Abul Taher

Last updated at 6:09 PM on 10th July 2011

It was a lavish party packed with oligarchs and mining magnates. Just the sort of occasion where you might expect to see Peter Mandelson.

But it seems someone was determined the world would not be allowed to see the Labour peer enjoying the lavish 40th birthday celebrations of his close friend billionaire Nat Rothschild.

Burly security guards used strong-arm tactics in a bid to prevent the former Business Secretary from being photographed as he joined other guests in Montenegro for the £1million event.

They snatched a mobile phone and deleted photos from the device and a camera memory card before ordering a Mail on Sunday reporter to ‘Take a walk’.

The three-day celebration for 300 guests in Porto Montenegro – ‘the St Tropez of the Adriatic’ – started on Thursday evening with a reception at a beachside restaurant, followed by the main event on Friday night, an open-air disco beside an infinity pool.

Lord Mandelson arrived at the party wearing a dark-blue open-necked shirt and white chinos and was immediately surrounded by security staff who ushered him towards a launch.

When the Mail on Sunday reporter tried to take a picture on his mobile, the bouncers swooped.

One 6ft guard with a strong East European accent said ‘Let me see your phone’, as he snatched it away.

He then deleted the only picture of Lord Mandelson the device contained. Handing the phone back, he told the reporter: ‘No pictures here please.’ Another heavily built security guard said: ‘Take a walk now. Just take a walk. I don’t want to see you here ever again.’

An MoS photographer was also forced to delete all the photographs he stored on a camera memory card and told to leave immediately.

Elusive: Mandelson pictured in London, left, but not at the lavish party for his friend, Nat Rothschild, right

Guests at the party – who were entertained until 4am by DJs flown in from the UK – drank Bellini champagne cocktails and enjoyed dinner at tables set out on each side of the vast pool.

The menu included a ham, figs and olive starter and barbecued Adriatic fish, followed by fruit panna cotta with wild berries – all teamed with £100 bottles of Bordeaux wine.

Lord Mandelson is believed to have stayed at the Aman Hotel on a private island at nearby Sveti Stefan. The hotel charges up to £2,600 per suite.

Russian oligarch Oleg Deripaska arrived at the festivities on his £70 million yacht the Queen K, in an echo of the most infamous meeting between Mandelson and investment banker Nat Rothschild.

Three years ago, Lord Mandelson attended a party hosted by Mr Rothschild on Mr Deripaska’s yacht on the Greek island of Corfu. During the trip he allegedly ‘dripped pure poison’ about then Prime Minister Gordon Brown.

The source of the leak was believed to have been the then shadow chancellor George Osborne. The Chancellor was not invited to this weekend’s celebrations, according to sources close to the Rothschilds.

Hideaway: Sveti Stefan in Montenegro hosted part of the lavish three-day party, and in which Peter Mandelson stayed

Other dignitaries who were invited included Peter Munk, 84, the Canadian billionaire who owns the largest gold mining company in the world; Tony Hayward, the former disgraced boss of BP who quit after the oil spill crisis in the Gulf of Mexico last year and is now one of Mr Rothschild’s business partners; and Milo Djukanovic, former prime minister of Montenegro.

Among other guests were historian Niall Ferguson and his pregnant wife Ayan Hirsi Ali, Russian model Sasha Volkova, Jimmy Choo shoe boss Tamara Mellon and British fashion author and socialite Plum Sykes.

The Sawiri family, Egyptian tycoons, were also there, apparently to check out the competition: they are building a £1billion marina and hotel development on the other side of the Bay of Kotor.

One royal guest was said to be King Kgosi Leruo Molotlegi. The leader of the Royal Bafokeng Nation - a semi-autonomous tribal region in South Africa which is rich in platinum - is a contact from Mr Rothschild's mineral business interests.

After dinner, a beaming Lord Mandelson watched as Mr Munk delivered a speech in honour of Mr Rothschild, lavishly praising his business achievements.

Mr Munk's massive yacht, the Golden Eagle, was one of two dozen moored in the marina. The largest, the Queen K, belongs to Mr Deripaska, a Russian aluminium oligarch.

Glamour: Jimmy Choo boss Tamara Mellon, left, and model Sasha Volkova added a touch of glamour

The festivites included a party on the jetty beside Oleg Deripaska's yacht, the Queen K

The billionaire banker Nat Rothschild pulled out all the stops for the lavish party. About five tons of food and drink as well as top musicians and entertainers have been brought into Montenegro for the extravagant three-day bash.

The investment bank chief flew high-profile revellers by private jet to a £520m marina he part-owns.

Long-legged young British women in short skirts and high heels emerged from sleek black Audis and Mercedes, bringing a touch of Chelsea to the Balkan resort.

One Porto Montenegro resident told the Sunday Telegraph: 'This place has become like a bar on Sloane Square overnight.

'A month or two ago we'd nicknamed it Porto Moscow, there were so many Russians around. But it's a completely different atmosphere with all the British here.'

A fleet of articulated lorries travelled from the UK to the south-eastern European country carrying equipment and furniture including 100 palm trees which will be used to create a calm and relaxed atmosphere.

It is thoughts nearly £100,000 has been spent on some of the wines from the Rothschilds' top Bordeaux estates as well as other alcoholic beverages.

Wealthy: Former BP boss Tony Hayward, left, and Chelsea owner Roman Abramovich attended the party

Rothschild and other billionaire investors have backed plans to establish an Adriatic St Tropez at Porto Montenegro, which is why he was probably so keen to host his party there.

The three-day no-expenses spared bash was an unofficial launch party for the development, built on the remains of a dilapidated Communist-era naval base.

The waterfront has had to be cleared of the rusting hulks of old warships. But they have salvaged one submarine, with plans to turn it into an exotic cocktail bar.

Plans are also in place for an international school and golf course to cater for super-rich residents, while a nearby commercial shipyard is to be turned into a maintenance yard for superyachts.

For hours before the start of the party the whole venue had been a building site swarmed over by mostly British construction workers.

Dress code for last night was 'disco chic' and the celebration was dubbed 'Nat's disco soiree' which took place around 65-metre infinity pool.

The birthday celebrations continued the next day with a 'hangover lunch' in the sunshine around the infinity pool.

Many of the high-profile guests are so discreet in their private lives security has been given cards to identify who's who.

The party is set to continue throughout the weekend.