Ali,

Seigfried Sasson was more in the 'Wilfred Owen' vein...

Youre thinking of Rupert Brooke, with the 'The Soldier', which is where the line "some corner of a foreign field that is forever England" comes from.

If I remember correctly, the 'jingo-ism' of Brooke's poetry seemed to go when his son was killed in action, part-way through the War.