Britain’s struggling economy has not been caused by Brexit alone and the European Union is not a “silver bullet” for boosting growth, Sir Keir Starmer has said.

The Labour leader repeated his argument that closer co-operation with the bloc is needed but said it would be a “mistake” to attribute all the UK’s problems to severing ties with Brussels.

In a Q&A following his speech at a conference hosted by the Resolution Foundation think tank, Sir Keir was asked about his claim in the Telegraph that the Tories had failed to grasp the opportunities of Brexit.

Resolution Foundation conference – London
Labour Party leader Sir Keir Starmer speaking at the Resolution Foundation conference at the QEII Centre in central London (Maja Smiejkowska/PA)

“It is a mistake to think that all of our economic problems are caused by Brexit. We had flatlining on growth for 13 years, way before Brexit was a word, way before there was a vote and certainly way before we left,” he said.

“So it is a mistake to think that the EU is a silver bullet.”

Labour has made clear that rejoining the bloc is a line it would not want to cross if it wins the next general election but has indicated it would seek closer economic ties, with Sir Keir previously suggesting “we don’t want to diverge” from some EU rules.

On Monday the party leader conceded there are areas where the UK can move with “speed and agility” that it did not have before and “we need to make the most of that”.

But he said “there is a better deal to be had if we do the hard yards and negotiate in good faith”, saying the current agreement is “not good enough”.

Labour will be seeking to win back parts of the electorate who voted to leave the EU in the 2016 referendum, and discussion of strengthening ties has been approached with caution so far.

It has insisted it would avoid “dynamic alignment,” where the UK follows changes from Brussels, and “we are not going to be rule-takers”.