British spectrum.

[mileslunn]

If you are doing an American comparison I would say this

GOP - UKIP and moderate GOP like right wing of Conservatives
Democrats - A mix of third way Labour (Blairites), Liberal Democrats, and moderate Tories (i.e. Kenneth Clarke types)

Conservatives - Blue Dog Democrats or what is left of the Mainstreet Republicans
Labour Party - Bernie Sanders type Democrats
Liberal Democrats - Hillary Clinton type Democrats

Compared to Canada where I live

British Conservatives - Similar to Canadian Conservatives although probably most like the Ontario PCs and Manitoba PCs.  Not quite as centrist as the old PC party or Atlantic PCs, but not as right wing as the federal Conservatives post merger or Alberta's UCP.

Liberal Democrats - Similar to the federal Liberals, Ontario Liberals, and Atlantic provinces' Liberals

Labour Party - Similar to the NDP with someone like Tony Blair being similar to Roy Romanow, Gary Doer, or Thomas Mulcair and in fact I kind of think he would vote Liberal not NDP if he lived in Canada while Corbyn is more like Niki Ashton but would be well to the left of most Dippers.

Canadian Conservatives - Slightly to the right of the British Conservatives otherwise would be similar to merger the British Conservatives and UKIP

Liberals - Most like the Liberal Democrats and the Blairite faction of the Labour.  Do have some who might be One Nation Tories but most of them are probably former Progressive Conservatives who couldn't support the merger.  Perhaps the best comparison of how Liberals would vote in British elections, would be BC, Saskatchewan, and Manitoba.  Otherwise federal Liberal: Provincially BC Liberal, Saskatchewan Party, or Manitoba PC then Conservative in Britain.  Federal Liberal but NDP provincially in those provinces than Labour in Britain.

NDP - Canada's version of Labour Party but not quite as big a tent.  The loony left is a lot more marginalized, but the third way faction is also much smaller too.  Otherwise the overwhelming majority of the party would fall somewhere between Tony Blair and Jeremy Corbyn on the political spectrum.  Ed Miliband is probably the closest to a typical NDPer.

[Kingpoleon]

If you are doing an American comparison I would say this

GOP - UKIP and moderate GOP like right wing of Conservatives
Democrats - A mix of third way Labour (Blairites), Liberal Democrats, and moderate Tories (i.e. Kenneth Clarke types)

Conservatives - Blue Dog Democrats or what is left of the Mainstreet Republicans
Labour Party - Bernie Sanders type Democrats
Liberal Democrats - Hillary Clinton type Democrats

Compared to Canada where I live

British Conservatives - Similar to Canadian Conservatives although probably most like the Ontario PCs and Manitoba PCs.  Not quite as centrist as the old PC party or Atlantic PCs, but not as right wing as the federal Conservatives post merger or Alberta's UCP.

Liberal Democrats - Similar to the federal Liberals, Ontario Liberals, and Atlantic provinces' Liberals

Labour Party - Similar to the NDP with someone like Tony Blair being similar to Roy Romanow, Gary Doer, or Thomas Mulcair and in fact I kind of think he would vote Liberal not NDP if he lived in Canada while Corbyn is more like Niki Ashton but would be well to the left of most Dippers.

Canadian Conservatives - Slightly to the right of the British Conservatives otherwise would be similar to merger the British Conservatives and UKIP

Liberals - Most like the Liberal Democrats and the Blairite faction of the Labour.  Do have some who might be One Nation Tories but most of them are probably former Progressive Conservatives who couldn't support the merger.  Perhaps the best comparison of how Liberals would vote in British elections, would be BC, Saskatchewan, and Manitoba.  Otherwise federal Liberal: Provincially BC Liberal, Saskatchewan Party, or Manitoba PC then Conservative in Britain.  Federal Liberal but NDP provincially in those provinces than Labour in Britain.

NDP - Canada's version of Labour Party but not quite as big a tent.  The loony left is a lot more marginalized, but the third way faction is also much smaller too.  Otherwise the overwhelming majority of the party would fall somewhere between Tony Blair and Jeremy Corbyn on the political spectrum.  Ed Miliband is probably the closest to a typical NDPer.

This completely ignores the fact that Stephen Harper is to the right of Mitt Romney, Marco Rubio, and the like on most issues.

[mileslunn]

Stephen Harper was fairly right wing although the GOP as a whole is definitely further right.  Romney flip flopped on so many issues tough to say but certainly Harper never tried to run on the stuff the GOP did on gun control (he favoured dismantling the gun registry, but not concealed carry), outright privatization of health care.  I would place Harper around the same spot on the spectrum as John Kasich, not as right wing as Rubio who is probably more like Nathan Cooper the interim Wild Rose leader or some of the nuttier ones like Rob Anders or Cheryl Gallant.  He only looks moderate because the GOP is so extreme.  Romney was a mix, definitely more moderate than Harper as governor of Massachusetts, but more right wing when running in the GOP primary.  He seemed to go wherever he thought the votes were and so since people saw him lacking principles, they rejected him.  On the other hand Paul Ryan is definitely to the right of Harper. 

Also Canada's Conservatives still has people like Michael Chong and there is no way the GOP today would allow someone like that in their party.  He would be purged with his views quite quickly while someone like Brad Trost or Kellie Leitch who are on the fringes of the Conservatives are pretty mainstream in today's GOP.