EU referendum: The vote is looking closer than ever - David Cameron's reputation is at stake

There are times when the obsession with gaining party political advantage can have unintended consequences. In a highly topical matter a move aimed at securing the Government's domestic electoral majority could rebound on David Cameron and George Osborne unless they move fast.

I refer to the impending referendum on Brexit. As opinion polls in favour of our remaining in the European Union have been narrowing, so has it become apparent that there is a marked difference between the voting intentions of young and older voters. Thus a recent opinion poll puts younger voters strongly in favour of our remaining in the EU, while among older voters there appears to be a majority in favour of Brexit.

Now, as the prime minister and chancellor know only too well, there is a whale of difference between voting intentions and voting turnout. Older members of the population are, on balance, more inclined to go to the polling booths than the young. Thus, it has been a noteworthy feature of this Government's budgetary measures that they have been biased in favour of pleasing the so called 'grey vote'. This has applied to pensions, travel passes and other 'concessions.'

But in order to vote one has to be on the electoral register. For many years people who 'came of age' were automatically placed on the register and duly informed. But things have changed. Now, as my own family recently discovered when our twins became 18, you have to take active steps to ensure that you are on the register and eligible to vote.

Rightly or wrongly, this relatively new policy has been interpreted as a deliberate move on the part of the present Conservative government to introduce a bias in the system. The argument is that younger members of the electorate, if they are eligible and bother to turn out at all, will be more inclined to vote Labour.

We return to the referendum result, which at this stage is looking perilously close, and certainly worrying the finance directors of 'corporate Britain', who are reportedly delaying investment plans as business becomes increasingly concerned about the implications of a possible Brexit.

The prime minister and chancellor have themselves staked their reputations on the outcome. It would be ironic if changes to the electoral registration system meant that, in a tight fight, younger members of the population suddenly found themselves ineligible to vote IN.

A recent Ipsos MORI survey of 1,023 British adults, conducted between 19 March and 22 March, found that 48% of the respondents think Cameron should resign if UK votes to leave the EU, while 44% think he should continue as PM.

It is clear that the IN campaign urgently requires a shot in the arm. One area where they could surely try harder is in the debate about 'sovereignty.' The truth of the matter is that, as Tata's intended withdrawal from South Wales demonstrates, when it comes to economic sovereignty, the Conservatives, from the premiership of Mrs Thatcher onwards, have already ceded a remarkable amount of power over decisions in this country to overseas investors.

I recall the late Sir John Harvey-Jones, a great chairman of ICI, then one of Britain's leading companies, telling me: 'When things get tight, you close your overseas operations first.'