asked the Chancellor of the Exchequer what criteria he will employ in deciding the priority to be given in the public investment programme to the introduction of a decimal currency system.

The greater part of the public investment programme comprises continuing requirements such as housing, health, roads and education. For the rest we look at all relevant factors, including, in particular, costs and benefits.

Is the right hon. Gentleman aware that, while he said in reply to a Question on 12th May that the costs and benefits of decimalisation must be weighed against those of many other things involved in modernising Britain, on 2nd June, replying to a Question asked by me, he said that the Halsbury Committee had described the benefits of decimalisation as incapable of being measured? If that is so. how can we possibly decide what the priorities should be for decimalisation in the public investment programme?

The hon. Member raises an ingenious point, but the real point is that we cannot measure exactly many of these things. We can, and do, form a judgment as best we can about the relative costs and benefits of particular projects.

Will my right hon. Friend use his influence to ensure that in the next Conservative Party manifesto decimal coinage is mentioned, and will he challenge the parties opposite to declare their policy in regard to decimalisation, just as the parties in Australia did?

That is hardly a matter of Ministerial responsibility.