A planned teachers' strike has forced some schools to close while others face significant disruption.

A group of 12 and 13-year-olds at Caldew School , Dalston, are no longer going on a geography trip to Keswick on Tuesday because of the national walk-out expected by members of the National Union of Teachers (NUT).

Trinity School in Carlisle has also been forced to scrap an awards service for its year eight pupils that had been due to take place at Carlisle Cathedral. The school hopes to reschedule.

They are just two of the casualties of the planned strike, as Cumbrian schools which could be affected warn parents of potential disruption.

Stanwix School in Carlisle and Thomlinson Junior School , Wigton, are among the primary schools to announce they will be closed.

Headteachers have been at pains to point out they must consider the health and safety of pupils as they reach their decisions.

They have also told parents they hope the union's national dispute with the government can be resolved.

There are about 3,000 NUT members across Cumbria.

Schools will be affected in different ways depending on the numbers of teachers who are members of the union.

Some of the largest schools affected include Trinity and Caldew.

In a letter to parents, Chris McAree, headteacher of Caldew School, confirmed that 20 of his 76 teachers are NUT members.

With the potential that more than a quarter of his teachers may not be in work on Tuesday, Mr McAree says he "simply cannot open the school for all students".

Mr McAree wrote: "As the majority of our students come to school by bus, many setting off before the required time for teachers to be present in school, we have no choice but to partially close the school on that day.

"This is further compounded by the fact we are unable to ask non-striking staff to cover for their colleagues who are taking action."

Caldew School will be closed for years eight, nine and 10. Those in years seven and 12 should attend as normal.

In relation to the excursion to Keswick being cancelled, Mr McAree said: "We are disappointingly not allowed to reschedule this event as this is against the regulations governing strike action in schools."

Trinity School , in Strand Road, Carlisle, faces a similar situation and will be closed for its pupils in years eight, nine and 10 too.

William Howard School in Brampton will only be open for year 12 students. Its year 11 start-up days scheduled for Tuesday and Wednesday will also run as advertised. Brampton primary will be closed.

But Kirkby Stephen Grammar School's headteacher Ruth Houston will be closing her school completely.

The Government has been urged to hold talks with NUT leaders in a bid to avert the planned strike.

NUT members voted by more than 9-1 in favour of industrial action following a ballot in a long-running dispute over pay and conditions.

An Education Department spokesman said it was "already in regular and constructive talks" with the NUT on pay and conditions and urged the union to call off the strike.

Schools across west Cumbria will also close or face disruption next Tuesday.

Ian Smith has decided that he can open St Benedict’s School , Whitehaven, to only those pupils in years seven, eight and nine.

Jonathan Logan, headteacher of Workington Academy , informed parents yesterday that the Stainburn-based school would only be open to pupils in years 10 and 12.

“The pre-arranged year 6-7 transition tutor meetings will still be taking place,” he added.

A decision by leaders of the West Lakes Academy in Egremont will be made, at the very latest, on Monday, according to its website.

Adrian Thompson, chair of governors at the academy, told parents: “Every effort will be made to give notice at the latest by the day before; but in case the decision has to be made on the day itself, we are asking parents to nominate a place of safety, which may be your home, to which your child can go if we have to close.”

Netherhall School in Maryport and Cockermouth School will remain open with teaching cover for any absences already arranged.

The impact of the planned action is also set to hit primary schools.

Those that have announced they will close include Derwent Vale Primary School in Great Clifton near Workington; St James Juniors , Whitehaven; Netherton in Maryport; Thwaites primary in Millom; Broughton Primary , Eaglesfield Paddle and All Saints in Cockermouth and Westfield Nursery and Primary in Workington.

Ewanrigg Junior School in Maryport will also be closed but the school’s residential trip to London is still going ahead.

Broughton Moor Primary School is likely to be closed on Tuesday. A number of classes at other schools will not be on.