Britain's dominant services sector has expanded more than expected but a separate survey suggested economic growth may have cooled towards the end of the second quarter of the year.

The closely watched CIPS/Markit purchasing managers' index (PMI) posted a reading of 58.5 for June.

That was a sharp increase from the 56.5 recorded in May where anything greater than 50 signals expansion.

Economists had anticipated a reading of around 57 for June.

Separately the CBI's latest growth indicator gave a reading of 14 per cent in the three months to the end of June.

That was down from the 33 per cent it had recorded in the three months to the end of May. A slowing of business and professionals services was blamed for the fall.

The research, which surveys hundreds of businesses across the manufacturing, retail and service sectors, suggested respondents are optimistic of growth picking up with a net balance of 32 per cent expecting improvements over the next three months.

Rain Newton-Smith, CBI director of dconomics, highlighted the uncertainty of the Greek situation as one factor which could derail growth and added: "Despite an easing in performance this month, activity over the quarter as a whole has been good. We expect the economy to sustain a solid pace of growth over the remainder of the year as lower oil prices and inflation continue to boost real incomes and consumer spending.

"But exporters face real challenges, especially from the impact of a stronger pound against the Euro and still weak global export markets."

In the PMI survey firms benefited from new product launches and other commercial initiatives which helped boost demand.

However there was a slight easing of new order growth which saw monthly backlogs of work fall for the first time since March 2013.

Chris Williamson, chief economist at survey compilers Markit, said: "The UK PMI surveys indicate that the pace of economic growth rebounded in June, recovering from what appears to have been a brief lull caused by the general election."

He said the services, construction and manufacturing PMI surveys this week suggested the UK economy will expand from 0.4 per cent growth in the first quarter of the year to 0.5 per cent in the three months to June.

IHS Global Insight's Howard Archer said: "The improved services purchasing managers' survey provides a serious boost for hopes that UK gross domestic product growth improved appreciably in the second quarter."