Today’s government reshuffle has brought promotion not just to some new faces but also some MPs with perilous majorities.

A total of four Tory MPs in marginal seats have now become ministers. All could be defeated by Labour on a swing of 4%: the kind of result that would make Ed Miliband the leader of the largest party in the next parliament and only a handful of seats short of a working majority.

The four at risk are:

• Anna Soubry, minister of state for defence and MP for Broxtowe (majority: 389)

• Amber Rudd, junior energy minister and MP for Hastings & Rye (majority: 1,993)

• Robert Buckland, solicitor-general and MP for Swindon South (majority: 3,544)

• Nicky Morgan, education secretary and MP for Loughborough (majority: 3,744)

A fifth minister involved in the reshuffle has long been on Labour’s hit list: Esther McVey, who remains employment minister although she is now allowed to attend cabinet meetings. She is MP for Wirral West, and has a majority of just 2,436.

A sixth name was tipped by the media, but didn’t get anything: Angie Bray, MP for Ealing Central & Acton, who has a majority of 3,716.

In all of these cases, Labour is the challenging party.

These new Tory ministers at risk of becoming prize scalps for the opposition now face something of a dilemma. Do they devote as much time as possible to their government duties, in the hope a higher profile will boost their chances of survival at the ballot box? Or do they try and limit the demands of Westminster in order to appease local party workers anxious to get their MP to show their face at another school fete and church service?

Of all the new appointments, Nicky Morgan should be most concerned. If Labour unseats the education secretary – moreover the person brought in to cool down the tempest caused by Michael Gove – it would be one of the most sensational stories of the election.