SCOTLAND'S two most senior politicians were caught in a highly embarrassing gaffe yesterday when they were overheard in a conversation in which ministerial colleagues were belittled just hours after Labour's victory.

Henry McLeish, the first minister, appeared to call John Reid, the Northern Ireland secretary and former Scottish secretary, a ''patronising bastard''.

During a conversation with Helen Liddell, the Scottish secretary, Mr McLeish also refers to Brian Wilson, the foreign office minister, as a ''liability''.

The private conversation was picked up inadvertently by Colin Kelly, a reporter with Scot FM, who had arrived at Labour's victory press conference in Glasgow yesterday.

Mr Kelly plugged his equipment into the party's sound system which had been set up in the room and began recording, a procedure which his Edinburgh-based radio station said was normal even though the news conference had not started.

Mr McLeish and Mrs Liddell were talking nearby, but did not realise the microphones they were wearing were live. Mrs Liddell appeared to be discussing her future in the cabinet reshuffle and whether she should go to London to await a call from the prime minister.

Spokesmen for Mrs Liddell and Mr McLeish later sought to play down the conversation, while a friend of Dr Reid said: ''John's got bigger and more important issues to deal with.''

Nicola Sturgeon, the SNP's shadow health minister, likened the ''astonishing'' outburst to former prime minister John Major's attack on his Tory cabinet ''bastards'' and said the remarks revealed the bad blood within New Labour.

Mr McLeish last night was believed to be planning to call Dr Reid with an explanation. It was later announced Mrs Liddell was to remain as Scottish secretary.