The boss of the world’s most valuable pharmaceutical company has told the BBC that the UK’s planning system puts companies off investing in the country.

Dave Ricks, chief executive of the obesity drug manufacturer Eli Lilly, said he had considered building a factory in the UK in the last decade, but chose another country instead.

He warned current planning processes were an “impediment” to building factories at speed, unlike in the US and Ireland.

“Mostly what they do is they pre-reserve land, they promise to cut through the red tape and layers of government,” Mr Ricks said.

Eli Lilly, along with its Danish rival Novo Nordisk, has developed a considerable lead over the rest of the pharmaceutical industry when it comes to obesity medication.

Its drugs, which include Zepbound and Mounjaro, are in such demand that the company cannot build factories quickly enough.

The country has operations in the US, Ireland and other European Union countries including Italy, France and Germany.

Mr Ricks said countries that “could present a path” in which the time taken to set up a pharmaceutical plant was reduced from five years to two was “very attractive”.

“In the UK – although I love visiting, it’s a wonderful county – it’s not the largest market so you have to overcome that with other attractiveness, whether that be workforce, asset delivery or economic incentives,” he said.

“You have to be candid, say ‘are we as competitive as we can be?’ And to date it’s been a little bit less, but I think it’s not unachievable.”

Both the Conservatives and Labour have made manifesto pledges on planning laws.

The Tories have said they would “simplify the planning system”, while Labour has vowed to reform it if it wins the upcoming general election.

A spokesperson for Labour said: “After 14 years of indecision, life sciences in the UK have been badly let down by the Conservatives.

“Labour has a plan for growth, including a new industrial strategy, and the UK’s life sciences sector is at the heart of it.”

The Conservative Party has been contacted for comment.

Changes to planning laws have been seen as a way of boosting economic growth. The strength of the UK economy has been a central battleground in the election campaign, with growth having been subdued in recent years.

Mr Ricks said the UK was “still in the mix” as a potential destination for a manufacturing site.

He urged the next government to consider how it could become “world class” in attracting investment.

“It’s a competition,” he said. “You have to make it easier and faster for companies to make that choice.”

A Liberal Democrat spokesperson said: “Years of Conservative mismanagement have undermined business confidence and led to countless missed opportunities for investment.”

They said: “We would develop an industrial strategy to foster a stable business environment with smart regulation to give firms the certainty they need, and overhaul the broken business rates system to boost our manufacturing industry.”