GlaxoSmithKline chairman Philip Hampton is to step down from the drugmaker, just a month after the firm fired the starting gun on its break-up.

The pharmaceutical giant, which has a plant in Ulverston, said that Mr Hampton, who was appointed non-executive chairman in 2015, had informed the board of his intention to step down and the search for his successor had begun.

In December, Glaxo agreed a tie-up with US rival Pfizer to merge their consumer healthcare divisions to create a business with combined sales of £9.8 billion.

The deal paves the way for a break-up of Glaxo into two separate UK-based companies - one focused on pharmaceuticals and vaccines, and the other on consumer healthcare - within three years of the completing joint venture.

Mr Hampton said: "Following the announcement, I believe this is the right moment to step down and allow a new chair to oversee this process through to its conclusion over the next few years and to lead the board into this next phase." No date for Mr Hampton's departure was given.

The firms are aiming to complete the joint venture in the second half of this year and it comes after pressure from shareholders.