Parliament has its youngest MP in centuries after the SNP's Mhairi Black was officially sworn in.

The 20-year-old, who is studying politics, opted to affirm as she joined others in completing the swearing-in process ahead of next Wednesday's State Opening of Parliament.

Ms Black's SNP colleagues Ian Blackford (Ross, Skye and Lochaber) and Angela Crawley (Lanark and Hamilton East) completed the formalities before she arrived at the despatch box.

She said: "I, Mhairi Black, Paisley and Renfrewshire South, do solemnly, sincerely and truly declare and affirm that I will be faithful and bear true allegiance to Her Majesty Queen Elizabeth, her heirs and successors, according to law."

Europe minister David Lidington was the first MP to swear in today and was soon followed by new Cabinet minister Amber Rudd, who has been promoted to Energy Secretary.

Conservative Bob Stewart (Beckenham) raised laughs in the chamber as he opted to take the oath.

Asked if a King James Bible was acceptable, Mr Stewart replied: "Anything."

The large SNP delegation continued to swear in, with new holders of previously safe Labour seats taking their place on the Commons' green benches.

Among them were Philippa Whitford, MP for Central Ayrshire, who took the oath in Scots, and Phil Boswell, who won Coatbridge, Chryston and Bellshill for the SNP.

Among those swearing in for the first time for Labour was Naz Shah, who beat George Galloway of the Respect Party to re-take Bradford West.

Jess Phillips, the new Labour MP for Birmingham Yardley, appeared to have her fingers crossed when she took the oath.

Also taking part this morning were senior Tories - including Amber Rudd, newly-promoted to Energy Secretary.

Labour's Richard Burgon (Leeds East) made his views on the monarchy clear as he opted to affirm.

He said: "As someone that believes that the head of state should be elected, I make this oath in order to serve my constituents."

Conservative David Davies (Monmouth) opted to take the oath in Welsh after reading it out in English - and revealed his ambitions for the Parliament.

He told MPs: "Now you know who to vote for when the chairmanship of the Welsh Affairs Select Committee comes up."

After a queue developed as MPs chatted to Speaker John Bercow, one sought to break the silence at the despatch box.

The SNP's Callum McCaig (Aberdeen South) asked a clerk: "How are you?"

She replied: "Yes, fine. Going all right?"

Mr McCaig said: "This has been quicker than I thought it might be."

Hannah Bardell, the SNP MP for Livingstone, appeared in the Commons to take the oath for a second time after making an error on the first attempt.

Other late appearances included Ken Clarke, the veteran Tory MP for Rushcliffe, who has been an MP since 1970, and Sir Keir Starmer, the former director of public prosecutions who is a rising Labour star after winning Holborn and St Pancras.