SNP MPs gather at Parliament
Nicola Sturgeon has presented the SNP's delegation of 56 MPs to Parliament and vowed to hold a face to face meeting with David Cameron shortly.
The party is due to formally appoint its Westminster group leader following a meeting of its MPs tomorrow, a role which takes on new prominence with an appearance at Prime Minister's Questions every week.
As the third largest party in Parliament, the nationalists expect to take up a front bench on the opposition side of the Commons, which used to be occupied by the Liberal Democrats before 2010.
Amongst the SNP cohort is Alex Salmond, former leader and former First Minister of Scotland, and 20-year-old Mhairi Black, the youngest MP in centuries.
The group was met by a huge press pack and onlookers wielding a giant Saltire flag.
Speaking to reporters, Ms Sturgeon said: "The SNP has worked long and hard in this election to make Scotland's voice heard.
"To have people in Scotland in such overwhelming numbers put their trust in us is fantastic but also is a big responsibility.
"We are determined to make Scotland's voice heard here in Westminster but we are also determined to be that voice for progressive politics that we promised to be during the election, to stand up to policies from a Conservative government that will damage Scotland and to make common cause with others of like mind from across the UK.
"I think the SNP will be the principled opposition in this place to the Conservative government."
She added: "I have had one conversation with David Cameron so far and his starting point seemed to be to implement the Smith Commission proposals. I don't think that goes far enough and I think that has to be looked at again.
"David Cameron cannot simply operate as if nothing has changed in Scotland - everything has changed.
"I've had one conversation with David Cameron, I look forward hopefully in the not to distant future to have more detailed conversations and at this stage I'll give him the benefit of the doubt and assume he will listen.
"We've agreed to talk face to face as soon as it can be arranged, I look forward to those discussions and to making progress on these issues."
Mr Salmond, who arrived at the event at the St Stephens' entrance to Parliament separately from other SNP MPs, said: "When I was last here we had to run around to look like a crowd - now we are a crowd.
"Obviously we are seeing a major change and shift in Scottish politics. Behind the number of MPs we are seeing a seismic shift, clearly Scotland is on a journey, there's no doubt about that whatsoever.
"But Nicola Sturgeon was quite right - the election result was not a mandate for independence or for a referendum on independence."
Asked how he would adjust from being first minister to a Commons back bencher, Mr Salmond added: "I loved being first minister but everything has its time and I think things are turning out not too badly."
He added: "The SNP group meets tomorrow so I'll be anxious to help in any way I can."
Angus Robertson, who led the SNP in Westminster in the last Parliament and made clear his desire to stay on in the role, said: "The huge transformation is not just that the SNP has 56 seats in the House of Commons, it's that we are the third party.
"That brings with it responsibilities and obligations, we will take part in every Prime Minister's Questions, everyone will take part in every debate, we will be represented across the select committees of the House and through the 'usual channels', which have been closed to us in our more than 45 years of permanent representation in the House of Commons.
"So it is transformational for the SNP and will give us an unparalleled opportunity to make our case and it is a hugely exciting prospect for all of us involved in it."