The U.K. is fast becoming a hub for tech startups -- in London alone, the number of tech companies grew 76 percent between 2009 and 2012, to 88,215.
Tech City, a U.K. government-backed initiative to encourage digital companies in an area of east London dubbed "Silicon Roundabout" (pictured), celebrated its third birthday last month. To mark the milestone, Prime Minister David Cameron pledged £15.5 million ($25.5 million) in new funding for innovative firms.
Here, we take a look at the top 10 tech startups in the country, based on The Deloitte Technology Fast 50, which ranked the U.K.'s fastest growing technology companies based on percentage revenue growth between 2008/09 and 2012/13.
— By Anmar Frangoul, Special to CNBC.com
Founded in 2008 by David McLeod (pictured) and Mike Cullen, Backbone Connect specializes in data centers – buildings which contain computer and storage systems – and offers clients support in areas including data backup and cloud computing packages.
It has enjoyed a revenue growth rate of 1,810 percent over the last five years.
Founded by Thomas Granier (pictured), Equal Experts creates bespoke software for large companies and institutions.
With offices in London and India, the company's model is based on connecting its "associates" – freelance IT professionals with between 10-15 years' experience in the industry – with blue chip clients including the U.K. Government, Telefonica, Rightmove and UBS.
This model enables Equal Experts to operate swiftly, matching problems to relevant experts.
For small businesses and freelancers, managing finances, sending invoices and filing tax returns can be nerve-wracking, time-consuming and complicated.
Founded by Ed Molyneux, Olly Headey and Roan Lavery (pictured), Edinburgh-based FreeAgent uses cloud-based accounting and bookkeeping software to help demystify the process.
Since its inception in 2007 with a staff of just three, the company has expanded rapidly, and now employs over 50 people serving 34,000 small businesses in over 80 countries.
With a revenue growth rate of 2,128 percent, FreeAgent is Scotland's fastest-growing tech startup.
Belfast-based production company Sixteen South's recipe for growth comes from marrying children's television with cutting-edge animation techniques.
Founded by Creative Director Colin Williams (pictured), Sixteen South produces kids' shows for broadcast on television and mobile apps.
The company has received plaudits for its storytelling, including a BAFTA award and two Emmy nominations.
Its use of technology to create a new type of 2D animation based on stop-frame techniques has enabled it to stay ahead of the competition and achieve a revenue growth rate of 2,214 per cent.
Monitise is a global leader in mobile banking services.
Set up in 2003, the company's founder, Alastair Lukies (pictured), saw a gap in the market and exploited it, offering consumers the ability to check their bank balance remotely.
His company's technology is now used by 350 financial institutions, has 24 million users and processes 3 billion mobile transactions worth $50 billion annually.
Online dating has transformed into a mainstream, ferociously competitive market. It is within this arena that Lovestruck, founded by Laurence Holloway and Brett Harding (pictured), has carved its own niche, appealing to eligible, busy professionals.
With a host of innovations such as its "behavioral recommendation engine," which learns from a user's activity on the site to match them with potential beaus, Lovestruck has attracted over 100,000 members in London and nearby counties, helping it achieve a revenue growth rate of 2,658 percent.
The company has expanded to offer dating services across the world, including in New York and Sydney.
Today, a dizzying number of mobile devices and contracts are available -- meaning that choosing a new mobile phone plan for your business can be a confusing, costly and drawn-out process.
Mobile Account Solutions uses its in-depth knowledge of the latest phones and plans to analyze a company's monthly invoices and find the most cost-effective deals. The Hertfordshire-based company has supported and advised over 3,000 businesses to date.
Mobile Account Solutions also guarantees delivery of replacement handsets within 24 hours, something which founder Danny Cox (pictured) says is, "almost unheard-of," in the industry.
With the big energy firms in the U.K. increasing their prices, knowing how big your gas and electricity bills will be is vital for consumers.
Cambridgeshire's AlertMe, whose CFO Jonathan Hull is pictured, has developed cloud based technology that allows homeowners to both monitor and control their energy consumption wherever they are using their computer or smartphone.
In 2012, AlertMe announced that it had secured a contract to supply a "Personalised Energy Efficiency Advice Service" to customers of British Gas, the U.K.'s biggest energy supplier.
In an increasingly connected world – there are 21.7 million home broadband connections in the U.K., according to communications regulator Ofcom – cyber-security has never been more important.
Founded by Mark Austin and Paul Kenyon (pictured), Manchester- and Boston-based Avecto specializes in Windows privilege management software, which enables companies to remove employees' administrator rights, thereby boosting the system's security and efficiency.
Founded in 2008, Infectious Media specializes in real-time bidding (RTB) -- an automated form of buying advertising space online.
The company has tapped into – and disrupted – the lucrative internet advertising sector by enabling advertisers to save money by bidding for ad impressions targeting specific consumers, rather than buying whole blocks of potentially irrelevant ad space.
Based in London, Infectious Media runs campaigns in over 50 countries, using complex algorithms to process 40 billion ad decisions every month. Pictured here are Martin Kelly, CEO and co-founder, and Zoe Steventon, Managing Director.