Harden's backs our campaign to put tap water on the menu

The backing of Harden's comes after more top restaurants and café chains said they agreed with the aims of the campaign.

The Standard wants diners to be routinely offered tap water alongside bottled still and sparkling when they place their order.

Richard Harden, co-founder of the guide, said: "We think the environmental case for tap water is so strong that it should be 'pushed' by restaurants at least as strongly as bottled.

"We don't agree with people who say this is just a token, or 'a drop in the ocean'.

"Hospitality has one of the largest carbon footprints of any UK industry and cutting down bottled water consumption is one of the easiest measures to take to start to reduce that footprint."

The campaign already has the backing of celebrity chefs, including Tom Aikens, Jamie Oliver, Antony Worrall Thompson and Aldo Zilli.

Today, the campaign gathered momentum as several more leading London restaurants said they would be putting tap water on an equal footing with the expensive and environmentally damaging bottled varieties.

Iqbal Wahhab, owner of Roast Restaurant in Borough, said: " Bottled water is a popular choice for guests at Roast and it is imperative that we provide it.

"But I am aware of the campaign to make tap water more easily available and I will instruct my staff to politely offer sparkling, still or a jug of tap water."

South Bank-based Skylon, which had one of London's highest-profile recent restaurant openings, said it would introduce "tap water equality".

Costa Coffee, one of Britain's leading coffee chains, is to follow suit.

In a statement, the company said: "Costa is delighted to be able to join this worthy campaign.

"We currently have more than 670 stores in the UK, so we're confident our efforts will help benefit the environment."

Yesterday Aldo Zilli's Soho restaurant became the first in London to display the Standard's Water On Tap campaign sticker.

Hundreds of dining rooms across the capital that have signed up will also be putting up the stickers following the move by Zilli Fish.

Other supporters of our campaign include the large chains Starbucks, McDonald' s, Wagamama and Strada.

Thames Water has calculated that a litre of water from its taps accounts for just 0.3 grams of CO2.

One litre of bottled water has a carbon footprint up to 300 times higher.