There is a very interesting and I think important pledge from the Conservative candidate for Richmond Zac Goldsmith. I'm reproducing it in full below from his website. Leaving the local politics aside, its significance is that it makes a well-argued case for something that is between the right to recall and direct democracy of mandating candidates. It's also honest about the realities of party politics. What Zac is saying is that yes, he is a Conservative candidate and he'll lose some arguments in his party but remain loyal to its line. Therefore, he is willing to vote for policies that he may not personally have agreed with, as do all party MPs in our system. Of course there may come a point where Burke's definition of an MP's autonomy kicks in and he has to vote on his judgement whatever the party or the majority of his electors think.

But Zac is adding a twist. There are three issues on which he has made direct pledges. He says he will not be able to serve in good faith if his party wins and they are not delivered. Therefore he has promised to resign and force a by-election:

If I am elected, and these promises are broken, I will therefore need to give people an opportunity to change their mind about having me as their representative.

He says this is not new or very radical, however I think it is new and it strikes a blow at the cosy assumptions of parliamentary government as we have known it.

I also think it is very welcome.

I have promised people in Richmond and North Kingston that if the Conservatives win the election nationally, there will be no third runway, that the key services at Kingston Hospital will be safeguarded and that there will be no charges for using Richmond Park.
 
Some of these issues aren’t of any national significance, but they are all major concerns locally, and if I am elected, it will be because a number of people have chosen to believe my promises, and the guarantees from the Conservative Party. I know that because that is what many people have told me.
 
If I am elected, and these promises are broken, I will therefore need to give people an opportunity to change their mind about having me as their representative. It’s not a particularly radical stance, and nor is it new. I have made this pledge many times.
 
But there are other reasons too. First; people do not believe a word they are told by any politician. We have all been badly let down, time after time, by the political elite. For instance, there is no one currently living under the flight path who hasn’t been lied to at least twice. My stance is also therefore a vote of confidence in the word of my Party. It shouldn’t constitute a risk.
 
Second; I had hoped that my campaign here in Richmond Park and North Kingston would be a clean one. I wanted to focus on the big issues, and debate them robustly with my opponent. Instead, I am forced to spend considerable time countering nonsense from the Lib Dem propaganda machine, Some of which I’ve answered here.  By making the promise I have made, I hope I can now move on to the real issues. 
 
Finally, I have been asked why I would stand down over these issues, and not other, more important issues. 

If I am elected, there will no doubt be times where I disagree with the direction of the Party. But the Conservative Party is mature enough to handle, and thrive on proper debate. If I lose the arguments on an issue that matters to me, I will have to improve my arguments.  
 
I want to see the extension of still more Direct Democracy. I want to see the Party engage in fundamental reform of the European Union, but backed up by a mandate in a referendum. I want to see continued progress on the environment. I want our courts to make judgements that reflect the instincts of the country. But you cannot expect to win every argument when you sign up to a mass political movement. That’s a reason to campaign harder, not resign.
 
The difference between these fundamental issues, and the three I listed earlier, is that on the former, I have made a direct pledge to local people: if they vote Conservative, they will – not might – see the results they want.