RURAL households continue to suffer slower broadband – even though a quarter of connections nationally are 'superfast'.

One in four UK residential fixed broadband connections is 'superfast', according to the latest Ofcom research.

The proportion of superfast connections – those offering headline speeds of 30Mbit/s or more – has risen from 5% in November 2011 to 25% in November 2013.

And the average superfast connection speed has continued to rise, reaching 47.0Mbit/s by November 2013 – an increase of 47%, or 15.1Mbit/s since May 2010.

The report reveals that at 17.8Mbit/s, the average actual fixed-line residential broadband speed in the UK is almost five times faster than it was five years ago.

But the UK picture is uneven, with a significant number of households – especially those in rural areas – experiencing considerably slower speeds.

Ofcom's indicative analysis suggests that the average urban download speed in November 2013 was 31.9Mbit/s, a 21% increase since May 2013

It found that the average suburban download speed in November 2013 was 21.8Mbit/s, a 22% increase since May 2013.

The research also suggests that average speeds in rural areas increased from 9.9Mbit/s to 11.3Mbit/s between May and November 2013.

But the sizes of the rural samples from which these averages were taken, however, are not large enough for the change to be deemed statistically significant.

This means the figures should be treated as indicative only.

Ofcom chief executive Ed Richards said: "The growth in superfast broadband and the rise in average speeds is testament to the investment in the sector.

"But the benefits are not shared evenly across the UK.

"There is more work needed to deliver wider availability of broadband and superfast broadband, particularly in rural communities but also in some locations within cities."

One key reason for the slower speeds in rural areas is the limited availability of superfast broadband services.

In addition, broadband speeds using the copper wire telephone network are generally slower in rural areas because of the longer distances to the telephone exchange.

Improving speeds in rural areas is a priority for the government which has committed funding to ensure superfast broadband is more widely available across the UK

It says it is on course to reach 90% superfast coverage by early 2016 and recently announced an extra £250m to extend superfast coverage to 95% of premises by 2017.