Michael Gove has warned fellow Conservatives that they may be driving Scotland towards independence by demanding additional rights for England.
The future of the United Kingdom is threatened by "English separatism" as well as by Scottish demands for independence and some party colleagues were showing "entirely the wrong attitude" towards Scottish sensibilities, said the education secretary.
Tories who try to reopen the so-called West Lothian Question by demanding "English votes for English laws" at Westminster or seeking a review of the financial settlement between the different nations of the UK, risk undermining the drive to preserve the Union, he warned.
Speaking at a Westminster lunch, Mr Gove - one of only two Scottish-born Tories in the Cabinet - acknowledged that Conservatives found it difficult to win a hearing north of the border for their argument that Scotland is stronger as part of the United Kingdom.
And he said this difficulty was increased if Scots had the impression that the English resented their perceived disadvantages under the current system.
"We need to persuade Scotland that its future is stronger in the United Kingdom than it would be if Scotland were to separate," said Mr Gove.
"We are stronger as a result of our common endeavour. We were stronger over the last 300 years. We have achieved amazing things in history. We pool risk more effectively and safeguard the weak more effectively and project our values more effectively because we stand together."
And he warned: "There is a threat to that from Scottish separatism, but there is also a threat - under-appreciated - from English separatism as well.
"I think there is a specific threat from my own particular tradition. There are some people on the right who say 'The Scots want to leave? Let them!'
"That seems to me to be entirely the wrong attitude."
He added: "That is why, when some of my colleagues say we need to revisit the West Lothian Question or we need to have a new settlement that is fairer for people in England, I say 'No, remember the big picture'.
"The country in which we were born is Great Britain for a reason. It is Great Britain because we stood together and stand together. If we turn inwards and against each other, I fear we will undermine something precious and our country will be a diminished presence in the future."
The House of Commons should constantly review the way it operates to take into account the changing reality of the devolution settlement, said Mr Gove.
But English MPs should not demand change in a "harsh tone which suggests that somehow we resent the fact that one part of the UK has had it easy or had a pampered existence at the expense of the rest".
He added: "I think that attempt to set one side against the other is profoundly unhelpful when it comes to the broader challenge we face, which is making sure we can stick together in order to deal with the challenges of the 21st century."
Scottish Liberal Democrat leader Willie Rennie MSP said: "Alex Salmond's frequent trips to lecture England on separation are designed to stir up this kind of dissent.
"Michael Gove is right to alert some of his colleagues to the dangers of pursuing this agenda. They should not play the first minister's game and focus on making the case for Scotland as a strong part of the UK."