Similar grille constructions, frequently also referred to as yetts, were used in Scotland over windows and other openings. These were typically fixed in place, often set into the jambs, sills and lintels.
The yett was frequently used as cheaper alternative to the portcullis, since it was simpler in concept, less cumbersome and more practical. However, it was also used within more complex defensive arrangements. The 14th century castle at Doune, in Perthshire, had a portcullis in the main gateway supplemented by a yett, with a second yett at the far bailey end of the passage. The yetts each had two leaves, with a wicket gate inserted within one of the leaves. Commonly, the yett would be placed behind a wooden door, providing additional security should the outer door be burned.
The earliest references to yetts date from the 14th century. Exchequer Rolls from 1377 refer to a "fabricated iron gate", part of the defences for David's Tower in Edinburgh Castle. Yetts were also appearing in other castles at about the same time. Craigmillar, built soon after 1374, reputedly contained a yett, and Doune Castle (c. 1380) still retains its original double-leafed yett; a similar double-leafed yett is present at Balvenie, but its age is uncertain. By the 15th century, yetts and window-grilles had became standard features within Scottish castles and towers.
Being a defensive structure, royal warrants were required before a yett could be added to any house or castle. These were frequently issued with other licenses for defensive features; for example, in 1501 John Murray of Cockpool was given a licence to build a tower at Comlongon with machicolations and "irneztteis and windois". Following the Union of the Crowns in 1603, efforts were made by the government to control the disorder and reiving in the borders. In November 1606 it was recognised that one of the impediments to the administration of justice in the area was the strength of the houses. Consequently, the Privy Council ordered that all yetts should be removed from all houses belonging to those lower in rank than barons.
Grated iron doors were found in England, but were constructed using a different method. For the English-style gate, the vertical bars all passed in front of the horizontal bars, and were riveted or fixed in place; the spaces were infilled with oak, making the gate solid. One notable exception, however, is constructed using the Scottish method: a yett from Streatlam Castle, now held at Bowes Museum. Streatlam was rebuilt by Sir George Bowes following damage in the 16th century; the Bowes family had connections in Scotland, which may have inspired the yett construction.
Records show that a yett constructed in 1568 for Kilravock Castle by a local smith weighed 34 stone, 3 lb, and cost £34, 3s. 9d. and "three bolls meal, ane stane butter, and ane stane cheese." Since yetts were immensely heavy, and there is no evidence to suggest they were prefabricated, it is likely each specimen was made locally rather than transported large distances, either by local smiths or itinerant specialists. Conventionally, window-grilles were built into the window-frames.