The deal involved a back-to-back transaction in which the Scottish Government acquired the two plants from Tata Steel and immediately sold them to Liberty House.

The steel processing mills were mothballed by Tata several months ago, threatening the loss of 270 jobs.

A total 150 jobs are expected to be created in getting both mills back up and running, with the possibility of further posts once production ramps up.

Sanjeev Gupta, executive chairman of Liberty House, said: “We’re very pleased to announce that we have completed the deal to acquire Tata’s plate mills in Scotland and we now look forward to continuing to work with local management and the workforce to re-build these great businesses in the months ahead. We’re very grateful for the valuable support of the Scottish Government and the trade unions in concluding this deal. Our team are continuing to evaluate the opportunity to make a bid for other Tata UK assets.”

First minister Nicola Sturgeon said: “I am delighted that the final details of the deal to transfer the Scottish steel plants is now concluded and implemented. We are very grateful to Liberty for their foresight in coming forward to take up this exciting opportunity in Scotland and for the energetic and speedy manner in which they worked with the Scottish Government to help save these jobs. We look forward to working very closely with them in the future.

“When we convened the Scottish Steel Taskforce back in October we did so with a determination not to stand by and watch these plants close, but to do everything possible to secure a new operator, and to do whatever we could to make the plants an attractive proposition. I am delighted that that approach has proved successful.”

Scottish business minister, Fergus Ewing, who chaired the Scottish Steel Taskforce, said: “I was pleased to update the House of Commons Select Committee on this exciting news for the Scottish steel industry when I gave evidence to their inquiry this morning.

“Over the course of eight taskforce meetings and a lot of other engagement we made significant progress in five key areas to support the industry, namely business rates, energy costs, environmental issues, skills and procurement. It has been a team effort which has paid off and once again the steelworkers of Scotland will produce world class products from Lanarkshire.

“The individuals who worked for us from the Scottish Government, Scottish Enterprise, Skills Development Scotland and SEPA were outstanding in their effort and commitment to the task before us. I am truly grateful to all these public servants for their work, as well as to the local trades union reps and the management.”