The closure of Strangers’ bar, in the House of Commons, while an alleged spiking incident is investigated has thrown the spotlight on Westminster’s drinking culture and what goes on in its many watering holes.

You are certainly never far from a bar in the Palace of Westminster.

For centuries, British politics has floated along on a tide of booze. Drink is part of the fabric of the place, but the drinking dens of Parliament are not what you might imagine.

The bars reserved exclusively for MPs and peers – in the deeper recesses of the ancient building – such as the Pugin Room or the Members’ Smoking Room (which is now non-smoking) may have the feel of a Mayfair gentlemen’s club, all leather armchairs and hushed tones.

But the most popular venue on the estate, The Woolsack, is more like a traditional British pub that you would find in any market square or High Street.

Until 2018, it was called the Sports and Social Club but was rebranded and placed under new management after it gained a reputation for drunken brawls and other misdemeanours.

Slightly shabby and old school, with its wood panelling, trophy cabinets and a carpet that has seen better days, it does a roaring trade with a younger, after-work crowd.

This is where researchers, Parliamentary staff and the occasional MP come to talk shop and catch up with gossip.

It is not easy to find, tucked away in a courtyard between loading bays with no sign outside, adding to the clubby sense of exclusivity that must be part of the attraction.

It’s open to passholders with a maximum of two guests and taking pictures or filming is strictly prohibited.

The prices are attractive too. You can get a pint of House of Lords lager for £4.30, for example, a pint of San Miguel for £5.25 or a small glass of Sauvignon Blanc for £5.60.

This is pretty cheap for central London. Similar drinks at pubs within easy walking distance of Parliament, such as the Red Lion, the St Stephen’s Tavern or the Marquis of Granby would set you back a bit more (according to our extensive research).

The Parliamentary authorities insist drinks on the estate are not directly subsidised – and are “benchmarked” against prices in the outside world.

But the Commons catering department, which oversees 27 bars, restaurants and cafes, as well as banqueting services, was subsidised by taxpayers in 2022/23 to the tune of £6.4m, according to the annual accounts.

Until it was closed, Strangers’ bar also did a roaring trade, particularly in the summer months when it serves drinks to thirsty punters on the Commons terrace, enjoying spectacular views of the Thames.

It is smaller and has a more upmarket feel than The Woolsack, but has also seen its share of bad behaviour over the years.

When late night sittings were more common, it would be packed with increasingly inebriated MPs and party whips, trying to keep them in line.

Journalists have traditionally headed to Strangers if they want to a catch a word with an MP.

(The Westminster press pack have their own bar and café, Moncrieff’s, named after the late, and legendary, Press Association reporter Chris Moncrieff, but few seem to use it.)

Along the corridor from Strangers, you will find function rooms which are another hub of Westminster’s social life, playing host to receptions and events most evenings where the (free) booze flows.

Speaking on condition of anonymity, one member of the catering staff tells me that the excitement can sometimes go to guests’ heads.

“I’ve never seen anyone throw up. I’ve seen four or five pass out,” he says.

The majority of MPs are polite and courteous to the staff, he says, but like most things at Westminster, when there is bad behaviour it tends to divide along party lines.

“The more pretentious Tory MPs will say ‘do you know who I am?’. Labour ones are more like ‘do you know how important I am?’,” he laughs.

One thing he has noticed is that the new intake of MPs seem to be a less boozy crowd than their predecessors.

Last July’s general election saw an unprecedented clear out of MPs, and many of the 350 new MPs are younger, and more likely to have school age children.

One of the new intake, Liberal Democrat Steff Aquarone, 40, thinks Westminster’s bar culture is well past its sell by date.

“This one of the few remaining places where it’s still possible to drink at lunchtime in the workplace. Most of the rest of the world of industry has moved on from that.”

The North Norfolk MP says this is “problematic” because “it creates all sorts of circumstances where behaviours that are not only undesirable but in some cases wholly toxic end up becoming accepted as the price of socialising”.

Commons leader Lucy Powell argued this week that it was safer for MPs and their staff to drink in Westminster’s bars, where they are protected by security guards and codes of conduct, than in ordinary London pubs.

Aquarone says he understands Powell’s point but, he argues, some people in Parliament need to be protected from colleagues.

“If I wanted to go for a drink with my team, I could choose anywhere in London where no one would know who we were and no one would know that we were there and that’s actually a far more secure way of having a safe night out.”

One new Labour MP said with many of the new intake their 30s with young children, there may be some drinking on a Monday night when there’s no vote until 10pm, but MPs are more aware that they shouldn’t be drinking with staff.

The terrace provided a good place to get to know new colleagues last summer and were bonding over booze, but the Labour MPs of old who had a pint at lunchtime are gone, they said.

In fact, some new MPs are pushing for Parliament’s bars to be closed at lunchtime, or even shut down altogether, as part of a modernisation programme.

This would not go down well with ordinary Parliamentary staff or many of the 14,500 pass holders with access to the pubs and bars on the estate.

“Parliament is a unique place, it’s like a village, why shouldn’t we have a bar? It’s the Houses of Parliament, not Ibiza,” one woman, who has worked in Parliament for nearly three decades, tells me.

She is enjoying an after work pint with a friend in the Lords Terrace bar, which has the slightly soulless feel of an airport lounge and tends to attract an older crowd.

They both think the public have got the wrong idea about Westminster drinking – friends are always disappointed when they get to see what the bars are actually like, they say.

“It’s just a place to relax and have a chat with your pals,” says the woman, as she drains her pint and pulls on her coat.

It’s certainly hard to imagine life at Westminster without pubs and bars, but changing social attitudes are lapping at the gates of its historic drinking dens.

Maybe one day they will call time.

Additional reporting by Ben Wright, BBC political correspondent and author of Order! Order! The Rise and Fall of Political Drinking.