The quality of education is improving, despite the impact of budget cuts, according to college heads.

But two principals accepted that student numbers and class choices had been reduced as they told MSPs that they were responding to Scottish Government priorities.

It follows a report by public spending scrutiny body Audit Scotland, which found college incomes had fallen since 2010-11, with a £56 million reduction in grant funding from the Scottish Funding Council (SFC).

The sector faces an overall 11% real-terms reduction in revenue grant funding from the Scottish Government between 2011-12 and 2014-15, auditors said.

The principals, from West College Scotland and Glasgow Clyde College, were questioned by members of Holyrood's Public Audit Committee. Convener Hugh Henry, a Labour MSP, asked how colleges could still offer the same level of service.

Audrey Cumberford, principal of West College Scotland, said: "There is a difference between the level and amount of activity, and the quality of activity."

The college has about 10,000 fewer students enrolled over the period, she said, but added: "In terms of the quality, actually our performance indicators are increasing and that remains our absolute key focus."

Susan Walsh, principal of Glasgow Clyde College, said 14,700 fewer students were enrolled than would have been at the former Cardonald, Langside and Anniesland colleges in 2009.

"Like Audrey has alluded to, the quality has actually improved in the last year," she said.