The convener of a Holyrood committee said it was "beyond disappointing" that the UK Welfare Secretary had again refused to appear before MSPs.

Members of the Scottish Parliament's Welfare Reform Committee had already urged Iain Duncan Smith to rethink his decision not to attend.

Mr Duncan Smith told them Lord Freud, the Work and Pensions Minister, would be in Scotland later this month and would meet MSPs. Committee convener Michael McMahon said they had accepted the offer of an informal briefing from Lord Freud.

But he hit out at Mr Duncan Smith. He said: "It is beyond disappointing that the Secretary of State has once again refused to give public evidence to our committee.

"Questions for his department have continued to mount. It is our duty to keep raising them with those responsible."

In his letter, Mr Duncan Smith told the MSPs he was "sorry that you may have taken my earlier response as implying I do not wish to engage with the committee".

He also said arrangements were being made for MSPs to visit the Edinburgh assessment centre of Atos, the private company which assesses whether people should receive disability benefits.

MSPs on the Welfare Reform Committee had hoped to question the Tory politician after a former health worker told how the benefits system had reduced him to a "blind beggar".