The 31 best places to work in the UK ranked by employees

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• Glassdoor releases annual ranking of best companies in the UK to work for.
• The list is based on anonymous feedback of employers given by staff on the website.
• Britain's best employer is not a major international tech giant, or big bank, but a UK-based utility company.

Recruitment website Glassdoor has released its annual list of the best companies in the UK to work for, based on anonymous employee reviews.

Glassdoor lets people anonymously leave ratings and feedback on their employers and Glassdoor has used that data to rank companies, giving them a rating out of 5. Companies had to have at least 30 reviews on the site and at least 1,000 employees to qualify.

Glassdoor gives all the company ratings to one decimal place, although companies which appear to be rated exactly the same can actually have slightly different ratings, and are ordered accordingly.

The list includes some of the world's largest and most recognizable companies, including Google and Apple. But it also features smaller, UK-focused firms.

"For employers, we know that a satisfied and engaged workforce helps drive financial performance," said Dr. Andrew Chamberlain, Glassdoor's chief economist.

"Glassdoor Best Places to Work winners are strategically investing in company culture, career growth opportunities and more, which also serves as a major recruiting advantage."

Check out the top businesses below: