An executive of the owner of Southern Railway is to leave the company for a top job elsewhere in the industry.

Dyan Crowther, who has been chief operating officer at Govia Thameslink Railway during the industrial relations and staffing problems at Southern, will be the new chief executive at HS1, the railway between St Pancras International in London and the Channel Tunnel in Kent.

She will join next year, replacing Nicola Shaw, who left HS1 in May.

Ms Crowther said: "I am delighted to be taking on this role. High Speed 1 is the UK's only high speed line which has transformed rail travel through Kent and into the continent.

"Its growth and performance in the last nine years are testament to its success and I look forward to leading the business and helping continue this success for customers and passengers alike."

Rob Holden, chairman and acting chief executive HS1 Ltd added: "As someone who joined the rail industry as a graduate, Dyan's experience made her an extremely strong candidate.

"She has a strategic understanding of HS1 as a business and a vision to take it forward. We are looking forward to welcoming her here properly at the start of our 10th anniversary year."

Nick Brown, former managing director for London Underground at Transport for London, will replace Ms Crowther at Govia.

Charles Horton, chief executive at Govia, said: "Nick has a first class pedigree in the transport industry, a wealth of experience and a strong track record of leading businesses in the rail and bus sectors.

"Nick's broad experience and intimate knowledge of the sector makes him ideally placed to help us achieve our business goals and deliver a better railway and excellent service for our customers."

Mick Cash, general secretary of the Rail, Maritime and Transport union said: "The appointment of Nick Brown opens the door to the real possibility of a new approach and new talks over the threat to the role of the guards, and the sacrificing of passenger safety, on the Southern Rail services.

"The union will be writing to Mr Brown today paving the way for those talks to begin as soon as possible.

"With 14 days of strike action set up right into December there is no time to lose in getting genuine and meaningful talks back on track now that there is a new chief operating officer in place.

"The appointment of Dyan Crowther as the new CEO at HS1, switching from GTR, raises serious union concerns about the company objectives going forwards and the union will be seeking assurances that this move does not represent a threat to our members jobs, working conditions and the safety regime on the international high speed services."