School chiefs and teaching unions are to hold crisis talks with Education Secretary Gavin Williamson today as pressure mounts for a month-long classroom closure to slow the spread of coronavirus.

Ministers have so far resisted calls to follow France, Italy and Ireland, which have sent children home for an extended Easter break.

British officials say crucial staff such as NHS workers would have to take time off work for childcare if schools were closed.

But amid calls for greater clarity from the Government, Mr Williamson will today meet school leaders to discuss the next move.

He was warned that one tactic, to allow larger class sizes if teachers are off sick, could backfire by spreading the virus between more pupils.

School chiefs and teaching unions are to hold crisis talks with Education Secretary Gavin Williamson today as pressure mounts for a month-long classroom closure to slow the spread of coronavirus

Another option understood to be under discussion by ministers for the exam boards to delay the tests until September, after students return from summer holidays.

Last night a Downing Street source told The Telegraph that discussions were ongoing, but refused to rule out exams being pushed back.

The talks were scheduled as ministers from Britain's largest teaching union, the National Education Union, said members were demanding to know 'why schools aren't closing if mass gatherings are to be suspended'.

In a letter to the Prime Minister, joint general secretaries, Mary Bousted and Kevin Courtney, wrote: 'Every day we are getting increasing numbers of questions from teachers and support staff asking why the Westminster government isn't following the pattern of other countries in calling for periods of school closure.'

Last week, Mr Williamson insisted that the 'impact of closing schools on children's education will be substantial, but the benefit to public health would not be'. He said he was 'particularly mindful' of increasing the strain on the workforce of public services such as the NHS.

Mr Williamson was backed by Association of School and College Leaders general secretary Geoff Barton, who said: 'Young people are safest and are best served by focus on the routines, the rhythms of learning.'

Ministers have so far resisted calls to follow France, Italy and Ireland, which have sent children home for an extended Easter break

However, Mr Barton urged the Government to suspend all Ofsted inspections immediately, with the exception of establishments with safeguarding concerns. In response, the watchdog said it would look 'very favourably' on schools that asked for inspections to be deferred during the outbreak.

Schools and colleges have been drawing up contingency plans to enable children to follow lesson plans online in the event of a long shutdown.

Writing in the Times Educational Supplement, primary school teacher Matthew Murray warned that relaxing maximum class sizes in primary schools 'could exacerbate an already worsening public health situation, as well as harm the wellbeing of school staff members'.

He asked: 'When the rest of society is seeking to avoid large gatherings, should this logic not apply to schools too?' Northern Ireland initially rejected calls to follow the decision of Irish Taoiseach Leo Varadkar to close all schools and colleges for two weeks.

But on Friday, Stormont First Minister Arlene Foster suggested schools will soon be closed for 16 weeks in the North.

Meanwhile, schools in Scotland are drawing up plans.

Larry Flanagan, of the Educational Institute for Scotland teaching union, said: 'There is a hope to get to the spring break without blanket school closures and then if incidents of the virus have increased, it may be necessary to close all schools.'