Plans by the Scottish Conservatives to charge students £6000 after university have been criticised by rival parties.

Under cross examination from Nicola Sturgeon on Tuesday’s live STV Holyrood election debate the Scottish Conservative leader Ruth Davidson revealed her plans to charge university graduates £6000. Davidson also stated that she would end free prescriptions and instead charge a sum of “up to £8”.

Davidson insisted however that it is not a "graduate tax” but a graduate contribution.

Davidson said: "First of all, it’s not a graduate tax. It’s a contribution after you have graduated and once you are earning money. We expect it to be within the region of just over £1500 per year you are at university. So that is a lot less than [in] England.

"We are also expecting that it will be able to raise more money. I think the issue is that you keep talking about university education being free, Nicola. University education in this country is not free. You know the cost of university education? The cost is 152,000 college places. The cost is the fact that poor people in Scotland are half as likely to be able to get into university than south of the border because you cut the bursaries."

The party's campaign director and deputy first minister John Swinney said: "Last night, under pressure from Nicola Sturgeon, Ruth Davidson was forced to admit her hidden tax plan to charge students thousands of pounds to go to university - and to force people suffering from ill health to pay unfair prescription charges. The Tory leader has yet to set out any detail on who would pay the charge, when they would pay it or whether the charge would increase.

"When tuition fees were introduced in England they were set at just £1,000 per year, before rising to £9,000 before the Tory government removed the cap altogether last year – Ruth Davidson has made no guarantee that they won’t do the same in Scotland.

Scottish Labour leader Kezia Dugdale said: "Tory plans for tuition fees and prescription charges would mean hidden tax rises on learning and on the sick. It says it all about the Tories when they won’t ask the top 1% to pay a single penny more but want students to pay £6,000 to learn and the sick to pay for their medicines. Labour supports free tuition and no prescription charges.

"Ruth Davidson’s callous shrug of the shoulders when asked about the bedroom tax tells you all you need to know about the Scottish Tory Party. They are just the same old Tories."

Lib Dem leader Willie Rennie said: "In the 1990s, as John Major’s government collapsed in chaos, the Conservatives hit people with 22 stealth taxes. Now Ruth Davidson wants to do the same in Scotland too. The truth is that Tories are only interested in cutting taxes for the rich. They would increase them for new graduates and everyone else.

"The difference is clear. People can vote for a transformational investment in education with the Liberal Democrats, funded by progressive changes to income tax, or for secret tax hikes on education and who knows what else with the Tories."

The party's co-convener Maggie Chapman said: "The Tories' aim with this extremely regressive policy is to load young people with yet more debt. At a time when many graduates struggle to pay rent and are faced with lower paid and less stable jobs than ever before, we must create an education system that supports graduates rather than penalise them with enormous debts.

Greens have always valued education as a social good - something that improves not just the individual but all of society. We should invest in it, not use it as a tool to get young people into debt and take away control of their life choices."

Conservative politician John Lamont said: "We've been consistent in our support for a graduate contribution for the entirety of this parliament and the last."

"The reason the Lib Dems have lost support in the last few years is because they signed a pledge to oppose tuition fees and then went ahead and backed them as soon as they got into government.

"Willie Rennie is really in no position to preach about student finance given his party's history of broken promises."