Direct Save Telecom claims it has recorded its largest period of growth over the last 12 months, driven by a 17% rise in its customer base.
The provider is widely known for offering the cheapest home phone and broadband deals in the UK, including its £1.95 unlimited broadband deal.
It has attributed the rise to customers no longer having reservations about switching from the 'big four' telecoms providers.
Direct Save's CEO, Stavros Tsolakis said: “Our sales have been improving month on month for some time now, I really think the UK consumer is finally beginning to realise just how much they can save by shopping around for their home phone and broadband.
“The exciting growth figures are attributed to a genuine sway in the way the general public choose their telephone and broadband providers."
The soaring sales have seen the company expand into new offices in the centre of Watford, which will be able to house an extra 50 members of staff.
That move comes after the company opened a new office in Birmingham last year, and two smaller offices in Slough and Croydon prior to that.
Mr Tsolakis added: “This is a very exciting time for us as we have been planning this move for some time now. It’s a big step forward for us as a company, everything about the new offices is better."