The number of Covid cases caused by the Delta, or Indian, variant in Norfolk has increased amid an overall rise in case rates.

Latest data shows Delta variant coronavirus cases have increased in all of Norfolk's districts.

And public health bosses say it now makes up the majority of Covid-19 cases which have been sequenced in five of the county's seven districts - Broadland, Great Yarmouth, Norwich, North Norfolk and South Norfolk.

The most recent publicly available data from the Wellcome Sanger Institute, covering the two weeks up to June 5, showed there were an average of 28 sequenced Delta variant cases in Norfolk per week.

That was up on the average of 14 cases per week over the previous two week period.

While overall coronavirus case rates in Norfolk remain low compared to the national and regional average, they have risen by more than 50pc in the space of a week.

According to figures for the seven days up to Tuesday, June 8, case rates in Norfolk went up from 10.2 cases per 100,000 in the week up to Tuesday, June 1 to 15.5 cases per 100,000 - a jump of 51.6pc.

Public health bosses in Norfolk said it is "too early" to know if that increase will be sustained or to what extent that is being caused by the Delta variant spreading more easily.

But a spokesman said: "Regardless, we continue to carry out enhanced contact tracing and outbreak management for all cases, to reduce the impact of any future waves of Covid-19 cases as far as possible."

In mid May, public health bosses had said there were fewer than 10 cases caused by the variant in the county and said that was "cause to be cautious". There have now been more than 40.

The overall Norfolk coronavirus case rate remains below the East of England case rate of 32.6 cases per 100,000, which went up 56.7pc on the previous week.

The county is also below the England case rate of 63.9 cases per 100,000, which increased by 70.2pc from the 37.5 per 100,000 the week before.

In Breckland, case rates fell 10pc, from 21.4 cases per 100,000 to 19.3, while in Great Yarmouth they were down 12.5pc, from 8.1 per 100,000 to seven.

They also fell in North Norfolk, where the case rate fall from 11.4 per 100,000 to 7.6 was a drop of just over 33pc.

But in South Norfolk they were up 575pc, from 2.8 cases per 100,000 to 19.2 and in Norwich the rise from 6.4 cases per 100,000 to 18.5 was a 189pc increase.

They were also up 75pc in Broadland, from 12.2 per 100,000 to 21.4 and by 28.6pc in King's Lynn and West Norfolk, from 9.2 per 100,000 to 11.9.

The average number of daily new cases in Norfolk in the last seven days is 22, compared to 15.3 for the previous week - a 44pc increase.

The total number of people tested for Covid-19 in the last seven days is 24,641, compared to 22,612 for the previous week - an increase of nine per cent.

As of Saturday, June 12, there were three people who had tested positive for Covid-19 in hospital - none in critical care.

The number of outbreaks - defined as two or more linked cases - has fallen.

As of Sunday, June 13, there were 38 open outbreaks, compared with 42 the previous week.

Fifteen were in schools, four in care homes and care providers and 17 in businesses and workplaces.

The latest statistics come ahead of an expected announcement from prime minister Boris Johnson that he will delay the June 21 final step of easing coronavirus restrictions.