Full size sketch of The Hay Wain (c1820), the most famous of Constable's 'six footers'. Victoria and Albert Museum

24 Hour Museum's six-foot-something reporter Graham Spicer goes to Tate Britain in London to take in Constable's 'six footer' masterpieces.

Constable: The Great Landscapes, which runs at Tate Britain until August 28 2006, brings together all of the celebrated English painter’s most famous landscapes for the first time.

Along with The Hay Wain, perhaps the most famous painting by an Englishman, the exhibition unites all six of his large paintings – the ‘six footers’ - of the Stour Valley in Suffolk as well as a number of earlier works and later large paintings.

“The exhibition focuses on one distinct aspect of his career,” said Dr Stephen Deuchar, Director of Tate Britain. “We focus on the phenomenon of the six-footers. All six pairs of six-foot landscapes are shown alongside their full size sketches.”

John Constable was born in 1776 is East Bergholt, Suffolk, the son of a prosperous corn and coal merchant. He joined London’s Royal Academy in 1799 but was not accepted for full membership until 1829, several years after his contemporary Turner.

Stratford Mill (1819-20). The National Gallery, London

Those who think of Constable’s painting as rather old-fashioned must remember that at the time he was something of a radical. After overcoming early problems with scale, from 1814 he started making small preparatory sketches ‘plein air’ (outdoors) which he later transferred to larger studies.

From 1819 he dramatically expanded the scope of his sketches when he began to make his celebrated six-footers, where the method of making full-size preparatory sketches was at the time a unique approach.

Anne Lyles, curators of the exhibition, said: “When we talk about these six-footers we should remember that Constable didn’t start painting these until half way through his career.”

“What this exhibition does is not only to reunite all these large pictures that define the Constable we know and love but at the same time reunites them with their full-scale sketches.”

The Lock (1824). Lent from the collection of Carmen Thyssen-Bornemisza, on loan to the Thyssen-Bornemisza Museum, Madrid

The first two rooms of the exhibition lead up to this stunning display, with an exploration of the development of Constable's style and working practice. The millstream next to his father’s mill at Flatford – the subject of The Hay Wain – appears in several of these earlier works, which helps to place this iconic image in context.

A recent discovery is also on display - the View In The Stour Valley Looking Towards Langham Church From Dedham (1805). This rare watercolour has now been acquired by Tate and this is the first time it has been on public display, having previously been in a private collection abroad.

His six pairs of scenes of the River Stour, made between 1819 and 1825, are the main focus of the exhibition, however.

They all feature pastoral scenes from a vanished world – boys fishing on the river bank, a moorhen disturbed by a leaping horse, barges skilfully navigated along the waterway – all featuring Constable’s trademark dramatic sky full of clouds.

X-ray of View on the Stour near Dedham showing the hidden figures and details that Constable later changed

Stepping into these galleries the viewer is immersed in Constable’s world, where he spent so many hours outside studying and painting the landscape.

Throughout this time Constable was constantly working on his compositional skills, which have been strikingly revealed by recent x-ray work on the sketch for View On The Stour Near Deadham. The x-rays show that a great number of alterations and corrections had been made before the piece was finished.

In the later 1820s Constable moved on from scenes of the Stour Valley and painted other parts of Suffolk and also subjects like Brighton, London and Salisbury. Hadleigh Castle (1829), another six-footer, painted soon after his wife Maria died, is dark and bleak, in contrast to the idylls of his earlier work.

Salisbury Cathedral From The Meadows (1831) brings religious symbolism to the fore, with a large rainbow framing the gothic cathedral. (Constable was a committed and enthusiastic supporter of Anglicism.)

Constable later painted scenes away from his native Suffolk. Chain Pier, Brighton (1826-7). Tate

A ‘mezzotint’ engraving of this scene, made around 1835, is shown alongside the main work – Constable was concerned that the rainbow should retain its otherworldly appearance and was heavily involved in the engraving’s production.

View of Brighton With The Chain Pier (1829) and The Opening Of Waterloo Bridge (1832) feature Constable’s trademeark style and attention to detail but are marked by their depiction of the modern (at the time) buildings and crowds of people - and they make an interesting contrast to the Suffolk paintings.

The exhibition concludes with a selection of Constable’s studio materials – his paint box, palette and brushes – and then moves onto a room with two interactive screens that help to show the artist’s method of working.

The first reveals the full x-rays of the View On The Stour Near Deadham sketch and the second shows how Constable scaled up his small early sketches to make his large canvasses.

With a total of 70 works on display there is enough diversity to get a real feel of Constable’s range of subjects, but it is the six pairs of six-footers that really steal the show.