The Manor of Leighton Buzzard alias Grovebury was the principal landowner in the town before the 19th century. Bedfordshire & Luton Archives & Records Service has a full run of court rolls from 1393 to 1727 [KK619-715] and another full run from 1704 to 1867 [X288/1-23]. The service also has court rolls for other manor to own land in the town, the Prebendal Manor, from 1448 to 1459, 1588 to 1591, 1611 to 1622, 1627 and 1631 [KK792-1798]. A fair number of buildings in the High Street were originally copyhold and a detailed study of these court rolls would probably produce quite detailed histories for a number of properties and the sites on which they stand, though it would take many years of study.

21 High Street was listed by the former Department of Environment in 1975 as Grade II, of special interest. It is an 18th century building built in local bond brickwork with grey headers and red dressings. It has a Welsh slated roof behind parapet. The shop front was altered in the 19th century, though the doorway is contemporary with the rest of the property. The building has three storeys.

A project called Our High Street Revisited 1819-2000 by Leighton-Linslade Local History Research Group [CRT130Lei58] aimed to use directories and census records to try to establish as full a history of use of the building in the High Street as possible. The results for Number 21 are as follows:

• 1806-1819: house of Margaret Pettit;
• 1841-1861: house of Charles Pettit;
• 1871: house of Elizabeth Pettit;
• 1881-1891: Henry Pettit, solicitor;
• 1903: house of Henry Pettit;
• 1924: house of Thomas Archibald Wood;
• 1927-1972: Henry Holmes & Sons, bakers;
• 2000: Jackson's, bakers;
• 2008: Take Away bakers

Under the terms of the Rating and Valuation Act 1925 every piece of land and building in the country was assessed to determine the rates to be paid on them. Leighton Buzzard was assessed in 1927 and the valuer visiting Number 21 [DV1/R56/61] noted that it was owned and occupied by Henry Holmes, baker. The "new" shop on the ground floor measured 13 feet square. The back sitting room measured 11 feet 6 inches by 12 feet and the kitchen and scullery 14 feet by 10 feet. There were also basement cellars measuring 15 feet by 11 feet, 11 feet by 12 feet and 14 feet by 10 feet which were "good". Upstairs was a half landing, a bedroom measuring 18 feet by 10 feet, a bathroom and W. C. and a sitting room measuring 18 feet by 11 feet 6 inches and a further bedroom measuring 12 feet by 11 feet. The third floor had bedrooms measuring 18 feet by 11 feet 6 inches, 18 feet by 10 feet and 12 feet by 11 feet.

A W. C. stood outside, along with a cupboard and a brick and slate bakehouse ("good") measuring 14 feet by 20 feet on the ground floor, a first floor flour store measuring 17 feet by 20 feet and a second floor store measuring 18 feet by 30 feet ("not used"). There was also an old wood and tile building ("poor") and a one stall stable and store with a loft over. Also outside was a covered corrugated iron weighing dock measuring 12 feet by 15 feet and a double deck oven ("new"). The valuer commented: "Note: front room being converted into shop" 12 May 1927. The shop is, at the time of writing [2009] still a bakery, as it has been for about three quarters of a century.