British bank Barclays has been named as the best U.K. company to work for, according to research by professional networking platform LinkedIn. 

LinkedIn's list looked at the U.K. companies that offer employees the best chance to build and sustain a career long term.

It conducted the research between January and December 2020, looking at the activity of its members, considering how companies fared across different categories including: the ability to advance, skills growth, company stability, external opportunity, company affinity, gender diversity and educational background. 

LinkedIn found that Barclays offered a strong mentoring program, as well as compulsory training on diversity and inclusion. Barclays' practices as an employer came under fire in 2018, when its CEO Jes Staley was fined for trying to reveal the identity of a person who had sent letters criticizing an employee at the bank.

Supermarket Tesco came in second place, with LinkedIn highlighting how it helped train employees to grow in digital confidence. Bank NatWest Group ranked in third place and LinkedIn said it also offered ample opportunity for employees to develop their skills. 

Siobhan Morrin, news editor at LinkedIn told CNBC via email that for many of the top employers on the list "on-the-job learning is a vital part of their culture." 

LinkedIn said that sectors which have adapted to meet the challenges of the pandemic dominated the rankings, including technology firms, grocery store chains and online retailers. 

Here's a rundown of the top companies on LinkedIn's list. 

Top 10 U.K. workplaces

1. Barclays —  Bank
2. Tesco — Grocery store
3. NatWest Group — Bank
4. BT — Telecommunications company
5. PwC UK — Professional services firm
6. Deloitte — Professional services firm
7. Sainsbury's — Grocery store
8. EY — Professional services firm
9. Upwork — Freelancing platform
10. BBC — Broadcaster

Check out: Here are the highest-paying companies in the UK in 2021, according to Glassdoor