David Cameron is spending the weekend finalising his first all-Conservative cabinet after his party won a majority in Thursday's election.
The PM has already reappointed Chancellor George Osborne, who has also been made first secretary of state.
Theresa May remains home secretary, Philip Hammond foreign secretary, and Michael Fallon defence secretary.
The Conservatives won 331 seats - five more than needed for a Commons majority - their first such victory since 1992.
'One nation'
Rival party leaders Ed Miliband, Nick Clegg and Nigel Farage all resigned on Friday after election disappointments, leaving their parties to consider who is best placed to lead opposition to the new government.
Mr Cameron, who promised to lead a government for "one nation", has already spoken to SNP leader Nicola Sturgeon, whose party won 56 of the 59 seats in Scotland.
The SNP is expected to press for even more devolved powers for the Scottish parliament, going beyond what was proposed by the Smith Commission after last year's independence referendum.
The new Westminster Parliament - which meets for the first time on 18 May - will see a record number of female and ethnic representatives, with 191 women (up from 143) and 42 from an ethnic minority (up from 27).
Meanwhile, the prime minster will need to replace Lib Dems who held cabinet posts in the coalition government - such as former Business Secretary Vince Cable, schools minister David Laws and Chief Secretary to the Treasury Danny Alexander - who all lost their seats in Thursday's vote.