Borough United were a minor Welsh football club based in Llandudno Junction who caused a shock by winning the Welsh Cup in 1963 before performing much better than anticipated in European football.
The club was formed in 1952 by a merger of two struggling neighbouring clubs Llandudno Junction (who had previously been successful in their league but had fallen into financial difficulties) and Conwy Borough. The new club represented something of a continuation for Llandudno Junction as they continued to play at their Nant-y-Coed ground and wear their maroon and white strip. They were soon established as a strong side in the Welsh League North, winning the title in 1958–59 and 1962–63. In the latter season the club also recorded their Welsh cup triumph, with victories over Rhyl, Denbigh Town, cup holders Bangor City and Hereford United setting up a final with Football League side Newport County In the two-legged final the club won 2–1 at home and drew 0–0 at Somerton Park to secure the win.
As a consequence of the success the club qualified for the UEFA Cup Winners' Cup and faced Sliema Wanderers of Malta in the first round. A 0–0 draw in Malta was followed by a 2–0 success at the Racecourse Ground in Wrexham — a more suitable venue than the tiny Nant-y-Coed ground with its single stand and spartan changing rooms — to set up a tie with Slovakian ŠK Slovan Bratislava. Borough were defeated 1–0 at Wrexham before losing 3–0 in Bratislava. The results were no disgrace however as the part-timers of Borough United had played well against a club that fielded five full internationals.