Its members include the likes of David Cameron, Bill Gates and Cristiano Ronaldo - as well as five Britons claiming to be mermaids.
And the latest glut of workers signing up with the LinkedIn website means the business-led social network has now amassed more than 15 million users.
LinkedIn is the world's largest online professional network with more than 277 million members globally.
The business was set up a decade ago, and in 2010 there were two million UK employees registered with the website.
The domestic milestone represents 50% growth since September 2012 when the company boasted 10 million members in the UK. Students emerged as one of the key drivers of this growth, and represented the fastest growing demographic on the site.
The current list of members in the UK includes nearly 375,000 engineers, 50,000 solicitors and 12,500 journalists.
It also features 744 people advertising themselves as magicians, 66 rocket scientists and 59 body builders.Oh, and the mermaids - join up to find out more.
The five employers with the most staff on LinkedIn in the UK are RBS, Barclays, Lloyds, Tesco and the NHS.
London has the most members of any other UK region signed up with LinkedIn, with 2.3 million people.
Birmingham is second with 284,000 people, followed by Manchester with 250,000 and Reading with 213,000.