BT will aim for higher minimum broadband speeds generally as well as tackling slow speeds in hard-to-reach parts of the country, its chief executive has pledged.

Gavin Patterson said BT was committed to helping to deliver a new universal minimum broadband speed of 5 to 10 megabits per second (Mbps) for homes and businesses - enough for everyone in the UK to use popular internet services such as high-definition video.

BT has come under attack from its rivals, which have said the ownership of the national telecoms network by BT Openreach has led to a "substandard experience" for consumers. Calls have been made for the competition watchdog, which has strong powers to shake up markets, to step in.

As well as the aim of a new minimum universal broadband speed, BT also plans to start upgrading homes and smaller businesses with "superfast" speeds to "ultrafast" technology. It said that 10 million premises will receive ultrafast broadband with speeds of 300 to 500 Mbps by the end of 2020.

Mr Patterson, who said that new technologies being developed by BT should help boost slow speeds in many areas, added that there would need to be "a supportive regulatory and government policy environment" in order to "bring about a commercially viable investment".

Mr Patterson said: "We want to forge an ultrafast future for Britain and stand ready to help government deliver the broadband speeds necessary for every property to enjoy modern day internet services, such as high-definition TV streaming and cloud computing.

"To achieve this, we need a collaborative effort across industry and government."

The announcements follow pressure from BT's rivals and others for a radical shake-up of the broadband market.

A spokesman for Sky said of today's announcements: "What the British broadband market urgently needs is radical reform, not calculated manoeuvring and caveats to protect BT's self-interest.

"Only a truly independent Openreach will unlock the investment, innovation and competition required to deliver the digital connectivity of the future."

A TalkTalk spokesman said that for many, the plans announced by BT will come as "too little and too late".

He said: "If the industry is to reach its full potential we need a level playing field that encourages competing providers to roll out the ultrafast infrastructure of the future."

The chief executives of Sky, TalkTalk and Vodafone UK have been among those highlighting an "urgent need for increased competition" in the sector, so that alternative providers are encouraged to invest and innovate.

They were among those who put their names to a letter in the Financial Times, which said that the ownership of the national telecoms network by BT Openreach has led to a "substandard experience for millions of customers and diminished opportunity for alternative providers to compete effectively".

The letter, which was also signed by the Institute of Directors, said that the Competition and Markets Authority (CMA) should undertake a full investigation.

In June, research by consumer group Which? into customers of broadband providers generally found that up to three-quarters of households are paying for advertised broadband speeds that they have never received.

Which? found that 74% are not receiving the promised headline speeds on their broadband packages - the equivalent of 15.4 million homes - despite nine in 10 people saying this was an important factor when choosing a provider.

The study also found that ''incredibly'' 98% of rural homes did not typically receive the advertised headline speed, while 31% of households in towns and cities were able to receive the maximum level.