SCORES of families affected by hepatitis C infection from NHS blood transfusions will lose compensation of up to pounds-45,000 because of the SSP sitin and expulsion at Holyrood, critics claimed last night.

One campaigner labelled the SSP quartet as "clowns", while Nicola Sturgeon, the SNP leader at Holyrood, wrote to Colin Fox, SSP leader, demanding he apologise to families. Around 80 will not be compensated because of yesterday's proceedings.

The exchanges followed unprecedented scenes in Holyrood when Colin Fox, Frances Curran, Rosie Kane and Carolyn Leckie forced the suspension of parliament with a sit-in demonstration about the right to protest at next week's G8 summit at Gleneagles.

They were banned from parliament for the month of September - when parliament resumes - without salaries, staff allowances and expenses, or access to their offices.

Their absence from the chamber later proved crucial when ministers were determined to limit the extent of compensation to families of those who have died from hepatitis C, with a cut-off date barring those who died before August 29, 2003.

Hundreds of Scots have already received payments of between pounds-20,000 and pounds-45,000 under the Skipton Fund scheme pledged by UK and Scottish ministers on that date.

However, relatives of those who died before then are not entitled to claim. When ministers sought to give the scheme legal status by including it in the Smoking, Health and Social Care (Scotland) Bill, Holyrood's health committee was able to amend it to scrap the qualifying date.

But an amendment proposed by Andy Kerr, health minister, reinserting the 2003 date, was passed by just 56 votes to 52. Under parliamentary rules, if the vote had been tied, by four more MSPs opposing Mr Kerr's amendment, it would not have been passed.

Bruce Norval, a haemophiliac from Fortrose, the Black Isle, and leading campaigner, last night branded the Socialist MSPs as "clowns" for preferring cheap publicity over practical help for those involved.

However, he added: "I am even angrier with the Liberal Democrats, who have consistently sold us out. It appears they would prefer to cosy up to their Labour pals than help alleviate the plight of victims of the worst public health scandal for a generation."

The SSP MSPs launched their disruptive protest during first minister's question time.

Mr Fox was quickly ushered from the chamber by officials, and police were summoned to help remove the three women MSPs from the seats occupied by senior ministers. The public gallery was cleared during a stand-off between police and journalists over their initial refusal to vacate seats.

When proceedings began 45 minutes later, George Reid, the presiding officer, said: "For elected members to act in such a grossly undemocratic fashion is an absolute contempt of parliament. They cannot hope to be simultaneously on the barricades and on the benches of the parliament. Those who claim to speak for others should never, ever deny that right and that privilege to other elected members."

On the day parliament rose for its summer recess, he used his maximum powers to suspend the four MSPs.

However, a special meeting of the Holyrood standards committee then unanimously recommended the draconian penalty of a month's ban, postponed until the parliament sits again in early September.

Brian Adam, the standards convener, said the SSP protest was "premeditated, disorderly and [brought] the parliament into disrepute". That proposal was agreed by parliament without opposition.

Two SSP MSPs were not present, including Tommy Sheridan, the former convener, who is on paternity leave. A spokesman for the SSP said later that the parliament had acted "as a lynch mob, and we're outraged at the lack of natural justice and human rights. We're taking legal advice, as the whole process is shot through".