Bletchley Park House

Bletchley Park House is a large house, now used as offices, dating from 1860 and significantly altered and extended between 1883–86 and around 1906 for Sir Herbert Samuel Leon, a Jewish financier, Liberal party politician, and prominent Rationalist.

The building is constructed of red brick in Flemish bond with ashlar dressings. The principal gables are half-timbered with pebble-dashed infill, whilst some other gables are tile-hung. The roof is covered in Welsh slate with a red tile ridge, and features brick stacks with clustered flues, ribs and bands. The windows are transomed wooden frames, with the principal windows featuring leaded upper lights. Decorative wooden barge boards and finials adorn the gables.

The house is a large, rambling structure of two storeys with a partial attic. The entrance elevation comprises six bays and displays lavish ashlar detailing including architraves. The entrance, located in bay two, is set within an internal vaulted porch protecting a panelled, half-glazed double door with side lights. The upper part is traceried and features a fanlight of leaded glass with coloured elements. Flanking the porch are hexagonal brick columns surmounted by panelled stone tops, which flank the base of a four-light oriel window with decorative base. Two seated griffins on bracketed plinths project from and are attached to the porch. A shaped pediment with an elaborate finial tops this composition.

Bay one is gabled and features a projecting two-storey canted bay with a prettied eaves band and cornice below a swept, domed metal roof. To its left is a single-storey wooden conservatory with traceried bays, formerly an open-sided loggia. Paired, gabled bays two and three contain an ashlar-framed triple window to the ground floor with gableted buttresses, and two canted bay windows above. Across bay four runs a three-bay embattled ashlar loggia fronting an elaborate panelled double door, with a canted bay window to the right and an inserted first-floor window. Bay six contains a polygonal two-storey bay window with shaped pediments screening a finialed polygonal roof.

The right return features three left-hand bays in the same style as the front, with the remainder being plainer. Attached to the right end is a dovecote-like structure: octagonal and of two stages, with a plinth, inserted ground-floor windows, an ashlar upper stage with two-light windows below a string course, and a plain tile roof with gablets and finial.

The rear elevation is plainer, featuring a tradesmen's entrance and a complex roofline. One roof has a louvre with a finialed lead cupola, and an embattled tower with blue-brick decorative work and a date stone is visible (a former steep hipped roof has been removed). The left return echoes the style of the front elevation, with ashlar canted and curved bay windows, paired gabled bays two and three with decorative half-timbered first-floor work, a shaped pediment to bay four, and a former loggia (much altered) across the right-hand bays.

The interior preserves high-quality and elaborate finishes, including panelling, panelled doors, decorative fireplaces, and decorative plaster ceilings throughout. The entrance vestibule contains stone columns and vaults. The entrance hall features an arcaded polished-stone screen wall and panelled area beyond, with an elaborate two-stage, columned ashlar fireplace surround, traceried panelling and painted glass to the roof. A room at the right end contains a Jacobethan fireplace and a coffered ceiling with floral-decorated plaster panels. The stairhall is panelled, with a ground-floor arcade and deep floral frieze, a decorative coved and coffered ceiling over the stair, and a fretted balustrade with carved surround and carved octagonal newels, above a panelled stairwell. The library features an elaborate wooden Jacobethan inglenook with overmirror, fitted bookcases and shelves, a fluted frieze, and a compartmental ceiling with decorative plaster panels. The ballroom displays linenfold panelling with a wall recess flanked by clustered wooden columns from which spring traceried arches, elaborate plasterwork to the frieze, and a coved, ribbed ceiling with pendant finials. The billiard room has brattished panelling and cornice, with columns supporting ceiling ribs and wooden trusses. Additional fireplaces, panelling, decorative doors, plasterwork and cornices are found throughout the first floor.

Bletchley Park House served as the headquarters building of the World War II operational centre. In the grounds stood the hut in which the vital cracking of the Nazi Enigma Code occurred. Churchill was one of the important visitors to the house.