MSPS’ are to be given an extra £3million to hire staff after party bosses agreed Holyrood’s new powers would increase their workload.

At present, MSPs can spend up to £62,300 hiring researchers and office staff, with most taking on two workers.

But after next May’s election, the figure will rise to £85,000, allowing them to take on three members of staff.

The move was revealed by Presiding Officer Tricia Marwick in a letter to MSPs, after it was agreed by the main party leaders.

She wrote: “Demands on members have already increased and will continue to do so.

“As you know, the parliament will assume substantial new powers during the course of the next session, including significant powers over taxation and welfare.

“It is important the parliament and its members are properly resourced and supported to scrutinise these powers effectively and hold the government of the day to account”.

She said current funding, for two workers, was “not fit for purpose” and should rise “in light of the increase in powers and the consequent increase in workloads for constituency and regional offices”.

Officials said the move would add about £3million to Holyrood’s expenses bill, which last year came to £12.5million.

They have recommended new pay rates for MSPs’ staff ranging from £16,800 for an office administrator to £40,500 for a senior “head of office”.

The move comes after MPs approved the new Scotland Bill, which will devolve extensive new tax and welfare powers to Holyrood.

From 2017, the Scottish Government will become responsible for raising income tax in Scotland and gain powers to top up UK benefits or create its own in devolved areas.