Two of the top bosses at Britain's largest energy supplier, Centrica, have stepped down, leaving their successors to deal with the volatility caused by coronavirus.

Chief executive Iain Conn and chairman Charles Berry have both resigned from the British Gas owner with immediate effect, the company announced on Tuesday.

Neither departure is likely to come as a surprise to investors.

Mr Berry has been on medical leave since the beginning of February, while Mr Conn had already said he would step down this year.

Finance director Chris O'Shea is set to step into Mr Conn's shoes until a permanent successor can be found, Centrica – which has a number of operations in south Cumbria – said.

Meanwhile, Mr Berry, who was told by doctors to reduce his workload, will hand over to long-time board member Scott Wheway.

"I'm acutely aware that I'm taking this role at a time when we need to navigate our way through the current volatility caused by the impact of coronavirus," Mr Wheway said.

"Protecting our employees and customers is a priority for us, particularly those who are vulnerable."

Mr Wheway acknowledged that his first task would be to find a permanent replacement for Mr Conn, promising to look at candidates both from inside and outside the company.

His job will be to find someone willing to take on what can be a tough role at times.

Since being appointed around half a decade ago, Mr Conn has several times been in the firing line of politicians, customers and his own shareholders.

His replacement will take over with the British Gas owner in very poor shape. Shares are down by around 80 per cent since he took over in 2015.

Mr Conn took the reins during a period when the Big Six energy companies' stranglehold on the supply market was being loosened.

Smaller suppliers, such as Bulb, Ovo and Octopus, none of which even existed much more than a decade ago, have eaten into the dominance of British Gas.

According to Ofgem data, British Gas's share of the energy market has dropped from 24 per cent to 19 per cent since the beginning of 2015.

Mr Wheway said: “As a business we remain focused on structural simplification, improving our efficiency and delivering growth in our customer-facing businesses.”

In Cumbria, Centrica operates gas terminals situated between Roose and Rampside near Barrow and has operations in Morecambe Bay.

It also operates a 49-megawatt battery storage facility, built on the site of the former gas-fired Roosecote power station in Rampside Road, which is able to come online in less than a second to meet fluctuations in demand and is able to hold enough power to provide energy for around 50,000 homes.