Drugs giant Pfizer has announced plans to close two of its three key UK supply sites, but insists the decision has nothing to do with Brexit.

According to media reports, the firm's manufacturing site in Park Royal, London, as well as its global cold chain packaging and distribution facility in Portsmouth will be closed in 2017 and 2020 respectively, with around 370 job losses in total.

"This review process has been going on since 2010 and the team just felt there were more production capabilities at the site in Belgium to support future demand and to ensure we can support the supply chain," explained a spokesman for the firm, as reported by The Telegraph.

"The UK has a tricky commercial environment and doesn't always link life sciences investment to the way patients use medicines, but this decision is not linked to Brexit or medicines access".

Pfizer sold its flagship UK facilities in Sandwich, Kent, back in 2012, but around 700 of its employees remain employed at the Discovery Park science and business hub which is now housed there, and it still currently employs around 2,700 people at sites across the country.