Everyone knows that hotel phone charges are steep, but I realised they’re nothing less than a full-blown rip-off when I was checking out of the Luxor, in Las Vegas. I’d called London from the phone in my room. Well, it would have cost 90p a minute on my mobile. How much worse could a land line be?

Try this: for 15 minutes, the Luxor tried to charge me $120. (I still have the bill – I’m thinking of framing it.) When I went red, growled and foamed at the mouth, they reluctantly knocked 60 bucks off.

The next day, I flew home, and what did I read? The Lanesborough, in London, a considerably swankier hotel than the Luxor, has made in-room calls to the USA and Europe free. Yes, free, gratis, buckshee, a veritable dial-all-your-pals-in-Albuquerque orgy.

How is it done? Has the Lanesborough got something on the high-ups at BT? I called the hotel. “There’s no trick to it,” I was told. “We still have to pay for the calls, but we’ve decided to pick up the cost.”

Laudable, but what exactly is that cost – for a call between, say, London and New York? You or I would pay 15p a minute with BT, or just 3p a minute from a budget supplier such as Onetel; New Yorkers can get calls the other way for 8 cents a minute from AT&T. But businesses do much better.

“It’s about 1p-2p a minute,” says Alan Burkitt-Gray, the editor of Global Telecoms Business magazine. “Big companies such as hotels can negotiate very cheap deals.”

So, maybe it’s two cheers for the Lanesborough, rather than three. Still, if they can do it, why can’t all the rest? We decided to find out which hotels give their guests a fair deal, and which are blatantly profiteering. Armed with Burkitt-Gray’s London-New York price guide, we called the reception desks of a range of hotels in each city and asked what they charged to call the other. It was staggering.

“NEW YORK is £3.95 a minute,” said the lady at the London Ritz brightly – in fact, she sounded rather proud of it, as if she were talking to a shareholder who’d be getting the money, rather than the sap who’d be paying it. The biscuit, though, was smugly munched by Claridge’s. “Calls to New York are £4.95 per minute, sir,” the concierge coolly informed me. I gurgled faintly. “And calls within London are priced at 95 pence per minute. If you’re the type of person who objects to us robbing you blind, frankly we don’t want you here.” Actually he didn’t say that last bit, but the tone in his voice did.

It’s worth mentioning Blakes, too, for a nice combination of opacity and greed. They didn’t seem to know exactly what they charged, but happily confided that American guests calling home ran up bills of “£400 to £500, easily”.

Maybe you’d expect all this from the poshies. What about the trendy end of the market? Sanderson – “the hippest hotel in the world”, according to GQ – weighs in at £4, and the celebs hanging out at the Metropolitan pay £2. Budget? The likes of Travelodge don’t have in-room phones, but the Holiday Inn Express in Southwark does – and charges a less-than-cheapo £1.30.

Over in New York, charges are more complex – connection fees, taxes, fluctuating rates – so we asked the front desks for a ballpark figure for a five-minute call. The worst offender was the themey five-star Dream Hotel, which didn’t quote exact fees, but said: “It’s $10.81 for the connection, then roughly $60 for five minutes.” Dream? Nightmare.

Ian Schrager’s achingly trendy new Gramercy Park left us hanging on for seven minutes before saying: “It’s in the region of $55-$60, sir.” At those rates, that hold-music rendition of Lullaby of Birdland would have cost about $80.

The London NYC gives calls to London free, but it’s a bit of a gimmick, capitalising on the name: other calls are pricey. The best was Radio City Apartments, a neat budget place on 49th Street, which sells phone cards to use from your room phone – $5 for 100 minutes to London. A fair deal at last. HOW DO the hotels justify their prices? Have they no shame? Well, yes, it appears a few have. After our buzz around the front desks, we rang the management at the worst offenders to ask whether this was their idea of value. Some (stand up, the Dorchester) wouldn’t comment; others (take a bow, Dream Hotel) just didn’t call back. Perhaps the communications budget wouldn’t stretch to it.

The Ritz, though, came out fighting: “Our service charges are calculated to cover the costs incurred in maintaining efficiency. Our telephone technology includes the latest and most sophisticated equipment available.” Hang on, didn’t Alexander Graham Bell invent the telephone in 1876?

The very nice PR director at Claridge’s sounded a bit put out: “I’m surprised to hear we’re the most expensive. We’d expect to stay in line with the five-star market. I really don’t have any more to say to justify the cost.” Sanderson and Gramercy Park also used the “Everyone else is doing it, so why shouldn’t we?” argument.

But one place geta our phone vote: the midmarket Hoxton Hotel, in Clerkenwell, opened by the Pret A Manger tycoon Sinclair Beecham last year. New York? Five pence per minute. Local? Three pence per minute. That’s more like it. I called Beecham. He’s a garrulous type.

“Look, I can get calls to New York for 2p a minute. I want to make a fair profit, so I charge 5p. You say people are charging £5? It’s insulting. Why would you do that to a customer, charge them 250 times what it costs you? They’re corporate muggers. You should value your customers, but that’s treating them like suckers.”

Quite. Look at the table (left) and you’ll see there’s no rhyme or reason to the charges. They’re not related in any meaningful way to what hotels pay for calls. They’re simply a measure of how blatantly, rapaciously greedy they are – and, presumably, how stupid or submissive they think we will be when they present the bloody outrageous bill.

So, are we stuck using our mobiles, with their slightly less outrageous roaming charges? Here’s an alternative plan: assuming they ever let me into a posh hotel again, I’m going to use the phone and ignore the bill, offering a reasonable sum instead – 15p a minute to New York is more than fair. If enough of us do it, they’ll have to get real. Come on – they can’t sue all of us, can they?

Additional research by Helen Brooks

The list of shame

LONDON HOTELS

Charge for a five-minute call to New York

Claridge’s £24.75, The Savoy £20, Sanderson £20, The Ritz £19.75, The Dorchester £17.25, Great Eastern Hotel £15, The Metropolitan £10, MyHotel Bloomsbury £7.50, Holiday Inn Express £6.50, One Aldwych £6.25, Hoxton Hotel 25p, The Lanesborough - Free

NEW YORK HOTELS

Charge for a five-minute call to London

Dream Hotel $70.81, Gramercy Park $55, The Mercer $54 60, Thompson $50, Hotel Chelsea $35, Trump Tower $32.50, Waldorf-Astoria $20.63, Four Seasons $17, W Times Square $14.95, Hotel on Rivington $9.75, Dylan Hotel $7.50, Radio City Apartments 25c,

Figures supplied by hotel front desks. Some charges approximate

The mobile option

SO, ISN’T the lesson just to use your mobile? It may be a better option, but it’s usually expensive too – much more than a fairly priced land line would be. There’s currently no limit on what companies can bill for roaming calls, but in August, the European Union will bring in a cap on charges – 33p per minute to make a call, 16p to receive one. It will apply only in the EU, so check your plan before you dial from elsewhere.