Vince Cable: I could still lead Liberal Democrats at 70 The Business Secretary, furthermore, is known to have good relations with Ed Miliband, the Labour leader. Well, our position must be quite clear - that it is equidistant between the two, and that it's up to the British public to decide which direction they want to go in. But if it was necessary to make a stable government then we would be willing in principle to work for either side. We've shown we can work with the Conservatives and in principle we should be willing to work with Labour if the circumstances were right. I ask the former Shell chief economist if he could envisage being chancellor under in a Miliband-led coalition. He leaves the question hanging. Well I think that's a bit of a flight of fancy but...we're equidistant, we're willing to work with either of the two main parties...if the necessity should arise, and my expertise is in economic policy, so...but I'm not fantasising about what job I have. What about the top job in his own party. Again, he is quite happy to leave the option open. The party's wish, and his wish, is that [Nick Clegg] should continue as leader and nobody's questioning that. I don't have an ambition. He points out that he has already filled the post, on a temporary basis in 2007 after the resignation of Sir Menzies Campbell (at the age of 66). He continues: "I've said that if the necessity arose then it's something I would consider. But I'm not pushing to do it, I've no ambition to do it. What all political parties need, like all employers, is a good mix of youthful enthusiasm and experience. Whatever the future holds, Mr Cable is clearly keen to carry on to fight for his own pet projects inside the coalition. He is, of course the prime architect of Lib Dem plans for a "mansion tax" on properties valued at more than £2 million. At one stage last year it seemed likely that either a form of the mansion tax, or extra council tax "bands" which again would see the highest-value homes face bigger bills, would come in, only for a revolt by Tory cabinet ministers to scupper it. Is the mansion tax now dead? "I don't think it's dead," Mr Cable replies, describing the present council tax system as "massively unfair" and adding: "You don't go to the poorest people in society and ask them to make further cuts." However, he concedes that "at the moment, on the Conservative side, there isn't any willingness to grapple with it at all." As Mr Cable is not shy of taking on his Tory coalition partners, I ask him if he can understand how "core Conservatives" feel let down by the agenda being pushed forward by the coalition, particularly over same-sex marriage, which is strongly supported by the Lib Dems. The Business Secretary has been married twice (his first wife died in 2001) and has disclosed he wears the wedding rings from both unions. Well I have had a traditional Christian marriage twice and have been very happy in that kind of structure. But I don't feel threatened by the fact that another group of people want stable, secure relationships which they call marriage. What I do feel strongly about, and where I think the anxiety has been, is that we should show respect for people's religious convictions and I think that's why it's very important that individual priests and religious denominations that do not share the view about gay marriage should be able to opt out. And the legislation does provide for that. And I think providing that religious conviction is respected, I don't have any problem with the way we're going. Last week Lord Lawson, the former Conservative chancellor, reinvigorated the debate about Europe (which, of course, divides the coalition) by declaring that Mr Cameron must lead Britain out of the EU in 2017. Mr Clegg immediately hit back by warning that such a move would put up to three million jobs at risk. Significantly, Mr Cable strikes a different note when asked if withdrawal could mean unemployment going up by up to three million. I think that is putting it in too extreme a way. It is certainly true that there are I think roughly three million people whose jobs depend on trade with the European Union. I mean to say that all of those people would be put out of work would be putting it in an extreme and unreasonable way but I think the main concern is the big uncertainty that would be created. What about Lord Lawson's other point, that the UK on it own would eventually thrive in trade terms, after taking an initial "hit" on withdrawal? Mr Cable comes close to striking a Eurosceptic tone (for a Lib Dem at least) when he accepts that "it may be that in the very long term you could find a way past that." Mr Cable remains focused, of course, on banking reform, where plans to ring fence banks" high street operations from their investment banking arms and forcing them to hold more capital in attempt to avoid a repeat of the crash of 2008 are well advanced. With interest rates low, in an attempt to boost the economy, savers, however, find themselves losing out at a time when the cost of living is rising. What is the Business Secretary's message for them? He admits it is a "genuinely tricky situation" because governments all over the western world have had to resort to "very unorthodox monetary policy in order to prevent a very, very deep depression." He adds: "It's not comfortable and I think what I would hope is that we return as soon as poissible to normal economic conditions with normal interest rates, but we're not there yet." Ministers have, he argues, taken measures to help savers including the "triple lock" on the state pension which aims to push back against the current system which can penalise those who have saved. The move to end the compulsory purchase of annuities will also help pensioners trapped by low long-term interest rates, he argues. Mr Cable, who shrugs aside Tory jibes that he is the "anti-business Business Secretary," denies he sees banks as an "evil empire" and praises some of the industry's leaders, including those at Barclays and Lloyds, as "people who are genuinely trying to change the culture." He adds: "I don't want to be negative about the positive trends in the banking system but none the less, there is a real problem that the banks are not supporting growth and we can see this in the trends in their lending and approval rates for [small business] loans." With this in mind I ask whether he welcomes recent speculation, which many believe is being encouraged by Mr Osborne, that the process of selling off the government's stake in RBS could begin soon, certainly before the next election. "I don't see a great hurry," he replies. We don't want to inflict a loss on the taxpayer...and there is a lot of structural change that needs to be done and business banking in the UK is highly uncompetitive. There is even a hint of menace, suggesting Mr Cable is wise to Mr Osborne's tactical plan to use an RBS sell-off as a general election weapon for the Tories. "I don't think that timing should be governed by an electoral cycle," Mr Cable smiles, "it should be governed by what's beneficial for the taxpayer and the economy."