Parliament's youngest MP Mhairi Black is spending her Westminster pay packet on drinks for her pals and meals in McDonald's, she's revealed.

The 20-year-old SNP representative for Paisley and Renfrewshire South - who is still completing her politics degree at university - insisted that her friends have put the onus on her to foot the bar bill whenever they're out on the lash.

She said: 'All my pals are like, "right, this round's on you". It's quite crazy'

And just like most students, she's admitted that she's more than partial to a late night trip to McDonald's after long days in the Commons.

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A picture uploaded by Glasgow North East MP Anne McLaughlin to Twitter showed Mhairi Black tucking into a lunch of bread and chips on the Commons terrace

Speaking about her new life in the capital while guest on BBC Radio Scotland's 'Off the Ball' football show, Ms Black said: 'Once you're down there you don't really see a lot of London.

'You're at your work till 8 or 9 at night, then when you leave you grab a McDonald's and go back to the hotel.

'Certainly I do, at least.'

Ms Black toppled Labour stalwart and former Shadow Foreign Secretary Douglas Alexander in May's general election as the SNP secured a landslide victory north of the border.

Having only just left her teens, she is still a student at the University of Glasgow where she has vowed to continue and complete her politics degree.

Speaking to show host Stuart Cosgrove, the Paisley MP said she had a 'brass neck' - slang for having a cheek - going back to her uni pals when she'd already secured a top job in Westminster.

Talking about going back to her classes after the election, Ms Black said: 'It was quite bizarre.

Having only just left her teens, she is still a student at the University of Glasgow where she has vowed to continue and complete her politics degree

'It was a brass neck walking into a room with people I've been studying with for years and they're all pulling their hair out applying for a million and one jobs and I'm like, 'Hi guys, how's it going?'.'

The topic of her university dissertation was, unsurprisingly, the SNP and she is now looking forward to graduating at the end of the month.

To get herself looking her best for Parliament, Ms Black has also been shopping in Asda for 'smart clothes' after arguing with her mother.

The MP said: 'It's not very hard to resist (pressure to dress differently) because I've been resisting my mum for the last 20 years.

'She's been trying since I was about two but we settled on going to George for some smart clothes.

'You need to be yourself and wear what you're comfortable in.'