Order! Order!

Now that the House of Commons has adopted "family friendly" working hours, the Commons Refreshment Department is facing mounting losses – MPs are taking advantage of their new-found freedom and departing when business concludes in the early evening. This has led to suggestions that the Catering Committee might consider opening some of the MPs' restaurants and bars to the public. For security reasons, initial access would probably be restricted to those visiting Parliament on organised tours that would take place after the House had risen at 7pm. Whether the subsidised prices would apply is doubtful.

At present, "strangers" can be entertained only as personal guests of MPs in several dining-rooms and bars in the Commons, the new Portcullis House and other office buildings on the parliamentary estate. Four private dining-rooms are also available for MPs to sponsor parties.

Were such a radical plan to go ahead, there would certainly be a renewed public interest in Parliament, and the facilities in Portcullis House would be the easiest to make available to the public. The Despatch Box, The Debate and The Adjournment will become associated not with speeches and points of order but, instead, with the last word in fast food and fine wining and dining for the hoi polloi. Those are the names of the restaurants in the fabulous new parliamentary building opened two years ago and designed by Sir Michael Hopkins, which is linked by an underground escalator to the Palace of Westminster. The restaurants, grouped together inside the magnificent atrium of bronze and glass, complete with rectangular water feature and ornamental fig trees, are popular with secretaries and research assistants.

The Despatch Box is a quick cappuccino-and-gossip stop, while cafeteria-style lunches are available in The Debate, which also offers snacks throughout the day. This is the firm favourite of the Millbank control-freak tendency of young New Labour apparatchiks. Healthy eating – Islington style – is the theme, with such items as fillet of cod with roasted garlic and caramelised shallots (£2.40) and Indian spiced strips of pork with naan bread and mango chutney (£1.60) proving popular choices for the wannabe MPs. They can expect to bump into Blairite junior ministers such as David Lammy or David Miliband.

But for a power lunch, or to plot against the leadership, Tory MPs prefer the waiter service of The Adjournment – Westminster's answer to The Avenue in St James's. It offers exotic delicacies for weightwatchers, and also caters for vegetarians. Popular starters include lemon grass and coconut cream soup (£1.25). Main courses of roast breast of guinea fowl on celeriac mash (£6.50) or spaghetti with wild mushrooms, basil and extra-virgin olive oil (£5.50) are popular, especially with Tory modernisers such as Michael Portillo. MPs like the generous space between the tables, with one commenting: "You can slag off the party leader to your heart's content without being overheard."

Old Labour and Tory traditionalists prefer the nursery food on offer in the clubland atmosphere of the rectangular Barry-and-Pugin-designed Victorian Gothic rooms in the main parliamentary building. They want chips, roast potatoes, suet and cabinet puddings, and they want them served in the oak-panelled Members' or Strangers' Dining Rooms, overlooking the Thames. All the crockery is stamped with the Commons portcullis, and souvenir-hunters steal the salt and pepper pots. The Members' is a huge, gloomy rectangular room with high ceilings and seating for about 200. It could easily be given over to the public with no security problems. At present, they are allowed in only at lunchtime (when "Strangers" prices apply), as long as an MP accompanies them, but the place is deserted in the evening, when it reverts to "Members only". Try the haddock and chips and mushy peas, or beef and Guinness pie (both £5.45 in the Members', or £8.25 in the Strangers'), rounded off with apple and blackberry crumble. It's here that old-timers such as John Prescott, or Tory squires such as Nicholas Soames and Sir Peter Tapsell, lose the fight against the battle of the bulge.

A half-way house between modern and traditional – perhaps the Third Way – can be found in the Churchill Grill and Dining Room, on the ground floor, adjacent to the Terrace. But that is for high days and holidays, as prices are noticeably higher – a first course of air-dried Cumbrian ham salad with figs costs £4.25. The daily roast from the trolley is £11.25, and a T-bone steak over-priced at £17.50. Already, during this week's half-term recess, it has been open to Commons pass-holders and their guests, so there is no reason why it could not soon be opened to a wider clientele.

In the summer, the Terrace Marquee, with its stunning view of the London Eye, is popular, but advance booking – especially on Buckingham Palace Garden Party days – is essential. It is a favourite of MPs' wives, who like to show off their hats and dresses before taking tea with the Queen. A buffet of smoked salmon, cold fresh salmon and langoustines draws in the seafood-lovers, and champagne (bottle of House of Commons, £22; Veuve Clicquot Yellow Label, £35) is the tipple of choice. The venue is ideal for the MP with small children, who can run up and down the Terrace. For those requiring just a quick snack, cafeteria-style, the options are the Terrace Cafeteria and the Members' Tearoom (Members only, and would remain so). Breakfast is fantastic value (egg, bacon, two sausages, mushrooms, hash browns, £2), while the tearoom offers cosy armchairs, all the newspapers, and Eric Forth and Dennis Skinner holding court to their acolytes. This is where the Prime Minister visits to reassure the troops – but only when he is in deep doo-doo.

Booze is on tap at all times in a variety of outlets. The Strangers' Bar – nicknamed "The Kremlin" – is the favourite of Labour MPs, and cabinet ministers often pop in when there is reshuffle talk in the air. It has a northern pub atmosphere. Posh Tories prefer the Smoking Room, but it is unlikely to be opened to the public; which is just as well, because the room is infested with mice, encouraged by the bitesized pieces of cheese always on the side tables. Churchill, Aneurin Bevan, Michael Foot and Sir Edward Heath all liked holding court here. When the House sat until the early hours, copious amounts of port and brandy were drunk between the divisions. Gin-and-tonics are a snip, however, at £1.65, and House of Commons claret a reasonable £8.50 a bottle.

Sadly, Annie's Bar, traditionally the haunt of MPs eager to leak stories to the press, has fallen into disuse and been moved to a dirty corridor next to the vehicle loading bay and service area. Nobody bothers with this anymore. That just leaves the Pugin Room, which offers aperitifs, coffee and cognac. Afternoon tea, complete with finger sandwiches, scones, cream and jam, and pastries is also available here, but the strawberry teas on the Terrace during the summer are even better, not least because this is the place to show off by waving to the passing tourist boats as their loudspeakers inform their passengers: "There are the MPs running the country." But if it is the people's Parliament, let's allow the people to use it.