in 1980. The bridge was subject to a £4 million four-month in-depth maintenance programme during 2011. Since the 1990s, there has been talk of increasing road capacity over the Menai Strait, either by extending the road deck of the existing bridge or via the construction of a third bridge. Design The opening of the Menai Bridge in 1826, to the east of where Britannia Bridge was later built, provided the first fixed road link between Anglesey and the mainland. The increasing popularity of rail travel shortly necessitated a second bridge to provide a direct rail link between London and the port of Holyhead, the Chester and Holyhead Railway. Other railway schemes were proposed, including one in 1838 to cross Thomas Telford's existing Menai Bridge. Railway pioneer George Stephenson was invited to comment on this proposal but stated his concern about re-using a single carriageway of the suspension bridge, as bridges of this type were unsuited to locomotive use. By 1840, a Treasury committee decided broadly in favour of Stephenson's proposals, however, final consent to the route, including Britannia Bridge, would not be granted until 30 June 1845, the date on which the corresponding Parliamentary Bill received royal assent. Around the same time, Stephenson's son, Robert Stephenson, was appointed as chief engineer for the project. At the Admiralty's insistence, any bridge would have to permit passage of the strait by a fully rigged man-of-war. Stephenson therefore intended to cross the strait at a high level, over , by a bridge with two main spans of , rectangular iron tubes, each weighing , supported by masonry piers, the centre one of which was to be built on the Britannia Rock. Two additional spans of length would complete the bridge, making a continuous girder. The trains were to run inside the tubes (inside the box girders). Up until then, the longest wrought iron span had been , barely one fifteenth of the bridge's spans of . As originally envisaged by Stephenson, the tubular construction would give a structure sufficiently stiff to support the heavy loading associated with trains, but the tubes would not be fully self-supporting, some of their weight having to be taken by suspension chains. For the detailed design of the girders, Stephenson secured the assistance of the distinguished engineer William Fairbairn, an old friend of his father and described by Stephenson as "well known for his thorough practical knowledge in