When the former chancellor Nigel Lawson launched Conservatives for Britain, one of the groups that will campaign for a No vote in the EU referendum, he warned that the other side would try to scare people into voting Yes and, this week, he appears to have been proved right.

At the launch of Britain Stronger in Europe, one of the groups that will campaign for Yes, its figurehead, the businessman Lord Rose, ran through a long list of what he said would be the terrible consequences of leaving the EU.

Leaving, he said, would be a leap in the dark that would risk Britain's prosperity, threaten our safety and diminish our influence in the world. It would also be hard to renegotiate the UK's existing trade deals and there would be no guarantee British jobs would be safe and prices would not rise. Lord Rose also suggested leaving the EU would cost every UK household £3,000 per year.

For Scots who experienced last year's independence referendum, all of this will have a very familiar ring to it. The Yes campaign for Scottish independence was by no means immune from negativity, but there was a time when Better Together and the UK Government seemed to let lose one attack on independence after another. Some might point out that the negativity won in the end, but it is useful to remember that in January 2012 the polls gave the pro-UK cause a 25-point lead, which was reduced to 10 by referendum day and it reasonable to assume that at least some of that change was down to the perceived positivity of Yes and negativity of No.

The campaigners to stay in the EU must avoid making the same mistake and focus on the solid reasons for staying in. They have to be honest, of course, about what they see as the risks of the UK going it alone, but even the No side seems to realise the dangers of too much negativity, with the newly-launched Leave.EU seeking to emphasise what they see as the positive reasons for leaving.

Sir Hugh Orde, the former president of the Association of Chief Police Officers who is also involved in Britain Stronger in Europe, says the campaign is not scaremongering, it is simply disseminating the facts. But the risks of too much negativity back-firing remain. British voters tend to back the status quo in referendums, and a vote to stay in the EU is by far the most likely outcome by a long way, but Better Together rather took its lead for granted in the early stages of the independence debate – the vote to stay in the EU must not make the same mistake.