The modern political debate is mostly Right versus Centre. The consensus holds.
Left/Right in politics has long since lost its meaning. The Social Democratic victory had two origins. The Government from the centre by Conservatives from 1951-1964 and the Government from the centre by New Labour 1997-2010. In between we had liberal democrats like Heath, Wilson, Callaghan and Major who did nothing to upset this consensus. The Thatcher era was the exception of course and many would see this as a necessary corrective. As a Social Democrat I think she went too far and regret that only the Falklands War and a divided Left permitted her to rule for so long. But once she was out of the way the norms were swiftly restored not to be strongly challenged again from Left or Right. Since Attlee there has been no Socialist Government and since Thatcher the prospects of a traditionally "Right Wing" one have vanished as well. Cameron's Government is to be deplored not because it is too right wing but because it is incompetent.
The voices challenging consensus are strong and almost exclusively from the Right. It is mainly the Tories on the Right who tease the consensus and I believe that, even though I disagree with them, it is healthy that they do. Rather less healthy is the unintellectual populism of UKIP who unlike the Tory Right like Douglas Carswell, Dan Hannan (etc.) has no rational, credible basis at all. Which may be why few Tories of any seriousness have joined Mr Farage!
What we miss in modern politics is strong articulate stating of the socialist case. Indeed few even claim to be socialists these days. I miss that not because I particularly want a Socialist government but because the debate arena is weekend by it being Right v Centre rather than Right v Left. I know the centre has won - and that we are choosing managers not leaders any more. But the debate is rather impoverished by this reality.