Bills he is claimed to have run up on an array of luxury amusements include two top-of-the-range Chevrolet 4x4s, a thermal night vision kit for his Hummer H2, dozens of designer watches and jewels, a selection of handguns and two Arab karaoke machines. One takeaway meal came to almost $800 (£391). And then there is the $2,500 item on a trip to a hotel in Casablanca that reads: "Girls: party night 5".

These, and scores of others, are detailed in documents filed to the high court in a claim against the ambassador, Prince Mohammed bin Nawwaf bin Abdul Aziz, a nephew of King Abdullah.

Last month, he was ordered to pay more than £3m to his family's former private secretary, Walid El Hage, a Briton of Lebanese extraction and a former director of an Arab bookshop in the UK, who spent many years as confidante to the ambassador and his father. He claims he spent the money on their behalf.

The 54-year-old ambassador ignored the court proceedings, and had judgment awarded against him by default. But he now says he is hoping for an "amicable settlement". A meeting with the El Hage camp has been arranged for next week and the prince says he is seeking to have the court judgment set aside.

El Hage's lawyer, Ian Bloom, says his client, who is abroad, declines to comment. But those close to him say he believes the ambassador's diplomatic immunity is uncertain, because the alleged debts were incurred before he took office.

In a normal case, a debtor's property could be seized. But under the Vienna convention, other diplomats and their London families currently get away with activities from shoplifting to refusing to pay the congestion charge.

According to the documents filed by El Hage, he picked up bills as the prince went on trips to Rome, Vienna, Casablanca and Paris in 2004 and 2005, immediately before his posting to London.

As well as conventional, if large, bills for hotels, cars and security guards, the lists include charges for a variety of the world's most sophisticated brand-name items.

There is a list of 43 luxury watches allegedly bought in just 18 months at a total cost of at least £350,000. They included a Patek Philippe for £23,000 and two Jaeger Le Coultres for £17,500 and £16,700.

In January 2004, it is alleged, the prince left Riyadh for a European trip. He bought cutlery from specialist Paris shops Curty & Fils and Laguiole for €22, 990 (£16,439).

His family also allegedly invested in the must-have female fashion item - a crocodile Birkin bag listed at €18,770. Outfits from the couturiers Lanvin allegedly cost a further €150,000.

A Beretta pistol (€6,761) also figures on the list, along with a Cartier watch (€27,000) and antique guns, shotgun, and swords (€66,000).

Back in Saudi, it is claimed the prince spent £1,200 on three ivory tusks with amber and turquoise, and a red and gold crystal set for £9,000. A fleet of Yamaha Grizzly, and Big Bear quad bikes set him back £13,000.

But this was a small sum compared with the $183,000 which went on purchase and freight charges from the US for five highly sophisticated Raytheon thermal night vision cameras, to be fitted on his H2 Humvee US-army derivative vehicle. A large US pick-up, a Chevrolet Avalanche, is listed as "full options $39,250".

A specialist off-road rally car, the Wildcat African Raid, built by a UK firm in Derbyshire, on a Land-Rover chassis is listed as £94,000.

In March, the prince went on a further trip to Austria and on to Casablanca. There was an alleged visit to the famous Swarovski shop on Vienna's Kartnerstrasse of which it is said "almost any self-respecting Viennese lady has a Swarovski necklace, bracelet, or pair of earrings". The total bill was said to be $25,000.

In Morocco, items read: "hotel extra suite expenses, rooms for girls etc $1,465 ... girls party night 5 $2,500... Moroccan sweets arrangement to take away $250 ... HRH cash in hand $20,000".

One striking purchase listed is an "ST Dupont lighter limited edition" for $1,769, which carries a mother-of-pearl and platinum rendering of the design of the Taj Mahal.

Back in Jeddah, the prince is said to have bought many Persian rugs, more vehicles and watches and gifts of amber. As well as some low-calorie sweets, he also allegedly splashed out on the import of a suite of exotic pets, (with cages) including parrots, mynah birds and a Dr No-style white Persian chinchilla cat.

A large selection of guns also figure on the alleged invoices These include two Czech CZ75D and CZ97B pistols, a French Famas assault rifle and a Micro-Uzi machine gun of Israeli origin. The Austrian Glock 18C "special tactical weapon" is described in one advertisement as "particularly popular with VIP security personnel. Nothing stops an assassination attempt faster than a hail of 9mm bullets".

According to the court claims, the ambassador's luggage of choice is Delsey and Zero Halliburton aluminium suitcases, whilst in cigars, his preferences run to the latest offering from Cuba - the Cohiba Siglo VI "Canonazo" brand. His alternative choice is alleged to be the Lusitanias Double Corona, described as "a truly great cigar" with "cedar wood, leather and cinnamon".

The PR grandee Lord Bell last night issued a statement on the ambassador's behalf. It said that El Hage had worked for the prince's father for 27 years until he suffered a stroke in 2002. "The nature of the relationship subsequently changed." Lawyers in Saudi Arabia were handling the claim, and had asked for receipts "in order to consider the expenses claimed and as appropriate to seek to reach an amicable settlement".