The UK services sector saw its strongest growth since September 2018 last month, in the latest sign of a rebound in the economy following prime minister Boris Johnson’s emphatic election win.

A closely watched survey by IHS Markit found that business activity rose for the first time in five months in January, with the sector’s purchasing managers’ index reading coming in at 53.9, well ahead of expectations.

PMIs are an indicator of private sector activity and are given on a scale of 1 to 100. Anything above 50 signals growth, while anything below means contraction.

“January data pointed to a solid recovery in the performance of the UK service sector, with business activity, new work and employment all expanding at a faster pace than seen at the end of 2019,” said IHS Markit on Wednesday.

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Respondents to the research firm’s survey said that improved business and consumer confidence had translated into rising demand from clients.

There was a “robust” improvement in order intakes, meaning that business expansion accelerated at its fastest pace since June 2018.

Service providers are now the most positive about the coming 12 months than they have been since May 2015, a year before the Brexit referendum.

But firms noted that the rise in optimism was contingent on a stable political backdrop and receding Brexit uncertainty.

“January's PMI surveys give a clear signal that the UK economy has picked up since the general election, as a diminishing headwind from political uncertainty translated into rising business and consumer spending,” said Tim Moore, an associate director of economics at IHS Markit.

A number of companies said they needed to hire additional staff in January, primarily because of an expected rise in workloads and signs that clients are increasingly willing to spend more.

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A composite PMI from IHS Markit, which combines those of the services and manufacturing sectors, also climbed in January. It hit 53.3, its highest level since September 2018.

Similar data from the UK construction sector on Tuesday indicated that there were growing “signs of a turnaround” in demand for housebuilding projects.

Activity in the construction sector continued to fall in January but at a much slower pace, according to the PMI for the industry. Optimism among building firms also hit its highest level since 2018.

Other closely watched indicators have pointed to a clear, if modest, rebound for the economy in the wake of December’s election result.

Business optimism has also ticked up and there has been an improvement in the housing market.