SCOTLAND's most senior judge, the Rt Hon Lord Gill, is due to give a robust defence of sweeping reforms proposed to the country's court structure when questioned by MSPs next week.

The Lord President of the Court of Session is due to appear before Holyrood's justice committee, which is examining plans for what is said to be the biggest overhaul of the system in a generation.

More than one in five sheriff courts is due to close under controversial proposals drawn up by the Scottish Courts Service and backed by the Scottish Government. The service says the move will lead to a £1.3 million annual saving in running costs as well as a one-off £3m initial saving in maintenance costs.

But critics, including lawyers, argue the closures of at least 10 sheriff courts and seven justice of the peace courts across the country would be a huge blow to the principle of justice being seen to be done.

They also say witnesses may not turn up to give evidence at trials if they have to travel further and also that the remaining courts will struggle to cope with increased workloads.

Lord Gill will appear on a panel at Tuesday's committee along with Kathryn MacGregor, his legal secretary, and Eric McQueen, the chief executive of the Scottish Court Service.

"Determining the future shape of Scotland's court structure is a serious responsibility. Doing so against a backdrop of significant change and in a time of severe pressure on public finances is a difficult task, with few easy answers," said Lord Gill in his foreword to Shaping Scotland's Court Services, which sets out the planned changes. "I am confident that the proposals in this report will contribute significantly to the success of the forthcoming civil justice reforms."

Kenny MacAskill, the justice minister, will be questioned earlier in the same session on the Scottish Government's Courts Reform (Scotland) Bill. The Bill sets out massive reforms to the work of civil courts, including raising the threshold for civil actions at the Court of Session in Edinburgh from £5000 to £150,000, with those being worth less heard in sheriff courts. They are based on recommendations put forward by Lord Gill in his Scottish Civil Courts Review, published in September 2009.

Christine Grahame, the SNP convener of the justice committee, said: "These are extremely important proposals that are being examined and my colleagues on the committee will no doubt put some robust questions to the Cabinet Secretary as well as Lord Gill and Mr McQueen.

"They will be questioning them on a range of things including court closures and about whether it is the right thing to do in terms of local access to justice. I think it will be a lively session."

Earmarked to close are sheriff courts in Dornoch, Duns, Kirkcudbright, Peebles, Rothesay, Cupar, Dingwall, Arbroath, Haddington and Stonehaven. Mr McQueen said more may follow. The service has insisted the existing court system is not sustainable and that radical action is needed to cope with a 20% reduction to its running budget by 2014/15.

It also pointed out that in general, people will have to travel no more than 20 miles longer than the existing distance to go to court and that for most people, attending court is a rare event.

The Law Society of Scotland, has warned that increasing the threshold to £150,000 for civil cases at the Court of Session could lead to a "deluge of cases and delays" at sheriff courts.

Kim Leslie, convener of the Society's civil justice committee, said the matter would be exacerbated by sheriff court closures.