Conservatives and Tories

I wonder if someone could answer this question.

We know the Conservative party evolved from the Tory party in the first half of the 19th century, but why are some Conservatives happy to be called Tories while others consider it a derogatory term most often used by their opponents on the Left?

I mention this because in 2014 a long-serving Conservative member of parliament attended Forest's 35th anniversary party at Boisdale of Belgravia and a fellow guest – a libertarian blogger – took him to task for something the Conservative-led Coalition had done in government.

I don't remember what it was but I do remember the MP took umbrage when his interrogator (not me!) spoke of “the Tories".

The term obviously rankled because the aggrieved MP was quick to put him straight. "We are not Tories," he retorted, "we are the Conservative party." And with that he walked off, unwilling to prolong the conversation.

It made quite an impression on me but I only write about it now because after mentioning the Scottish Conservatives in Monday’s post I noticed that on Twitter their username (or handle) is @ScotTories.

If anyone knows why a current Conservative MP should be upset by the term 'Tories' do let me know.