This article is more than 9 years old

This article is more than 9 years old

A German spy photograph of a ruined house in Northamptonshire surrounded by oddly marked fields, has revealed a secret unguessed at by the Luftwaffe cameraman: such important evidence of a lost Tudor garden that the site has been awarded Grade I status by English Heritage, ranking it among the most important gardens in Europe.

The garden's grass ring marks, shown clearly by the aerial, monochrome, photograph, are 120 metres across and almost certainly mark a Tudor labyrinth tracing in symbolic form the religious faith of its creator – a faith that finally cost the man his family fortune and his son's life, after the latter was exposed as one of the Gunpowder plotters.

In 1944 the photographer was probably disappointed with his efforts: the house and garden of Lyveden New Bield, near Oundle, and now owned by the National Trust, were undoubtedly peculiar but could have had no military significance.

The Luftwaffe images are now part of the US national archive, kept in Maryland, and were only studied closely when the National Trust ordered copies in the past six months.

The 10 concentric circles, which have almost vanished from sight at ground level through 20th century ploughing, were probably planted with the 400 raspberry and rose bushes referred to in letters of Sir Thomas Tresham, and now held in the British Library.

Tresham created the cruciform hunting lodge and its moated garden, which is riddled with Roman Catholic symbolism.

Tony Calladine, a heritage protection officer for English Heritage, said: "Its remarkable state of preservation and its association with Thomas Tresham, famous gardener, recusant and architect, make it one of the most extraordinary and unique designed landscapes in the country."

Mark Bradshaw, property manager for the National Trust, plans to carry out an archaeological survey to trace the foundations, and then perhaps a recreation of the original planting. He explained that the raspberries symbolised the passion of Christ, and the white roses Christ's mother, while the labyrinth itself represented a spiritual journey on the one true path – there is only one way through the circles on the ground to reach the centre of the maze.

The Treshams were staunch Roman Catholics, frequently paying hefty fines, throughout the dangerous years of Henry VIII's break from Rome and in the years beyond.

Thomas Tresham died in September 1605, leaving £11,000 in debts, with the garden still unfinished and the house left roofless: neither was ever completed.

Two months later his son Francis was exposed as being a member of the Gunpowder Plot.

He was also suspected of writing the mysterious letter that betrayed the plot before Guy Fawkes could blow up parliament and everyone in it.

Francis was imprisoned in the Tower of London, where he died aged 38 allegedly of natural causes on 23 December: like the mysteries of his father's garden, the affair has been debated ever since.

• This article was amended on 11 November 2010 to make clear that the Tresham family were staunch Catholics, not just Thomas Tresham the gardener and architect.