Using two passports at Heathrow

[chrisgd]

I have dual   British/Canadian citizenship. In the past when I travel to the UK I have shown my UK  passport and a Canadian citizenship card.

I now have a Canadian passport which, no doubt, will simplify the process of getting out of Canada and getting back in.

I'll be in the UK again next month. I'll leave Canada on my Canadian passport, but what should I do at Heathrow Immigration? With a valid British passport I should be able to

go through the shortest queue - BUT leaving as a citizen of one country and coming back as another may not be too wise these days.
I had thought of showing both at the UK passport holders gate. Should my Canadian passport get stamped anyway?
(Showing a non-stamped passport when I leave might sound alarm bells too)

What should I do? I prefer not to join the long queues of non-EU passport holders.

[edgy555]

I know that a lot of countries have a requirement that if you're a citizen, you enter under your passport (of that country.)  The US, for one, insists upon it.  So, I don't think you have a problem here.  Enter each country on the passport of that country -- no need (and in fact not advisable) to show both passports at immigration.