Former Galloway MP Ian Lang says the Tory party should only consider giving further powers to the Scottish parliament after this year's independence referendum.
Lord Lang of Monkton has told ITV Border's Representing Border programme that any further devolution of power from Westminster should be considered within the context of the UK as a whole.
Tory leader Ruth Davidson has promised her party, which is holding its Scottish conference in Edinburgh this weekend, will set out their ideas for strengthening Holyrood before the referendum on 18 September.
The Commission which she set up to look into the issue, chaired by Conservative peer Lord Strathclyde, will publish its findings in May.
However, Lord Lang - who was the Tory MP for Galloway between 1979 and 1983 and for Galloway and Upper Nithsdale up to 1997 - says the party should put all its energy into winning a 'No' vote in the referendum.
He tells Representing Border:
Lord Lang, who was Scottish Secretary from 1990 to 1995, adds:
Responding to Lord Lang, a Scottish Conservative spokesman said:
In a speech in March last year in which she announced the setting up of the Commission, Ms Davidson said:
South of Scotland and SNP MSP Joan McAlpine said that only a Yes vote will bring the powers Scotland needs.
You can see our interview with Lord Lang in full on Representing Border tonight at 10.45 on freeview in the South of Scotland or on line at itv.com/border