The Leyland Royal Tiger was an underfloor-engined heavyweight single deck bus or coach chassis, and sold well in the United Kingdom and overseas from launch.

It used the same units as the Leyland-MCW Olympic but with a substantial steel ladder-frame chassis generally straight in elevation but with an up-sweep over the rear axle,[1] to which operators could fit a coach-built body of their choice with the passenger floor about 3 ft (914 mm) above the road surface.

Steering was unassisted Marles cam and double roller,[3] all component assemblies (save for some special export orders) were built by Leyland and were proven, having been previously used in the Tiger PS2 and/or Olympic.

Although the 8 ft width was the majority choice most operators chose the vacuum-servo braking system, which was at its limits coping with a fully laden vehicle with an eight-ton unladen weight.

Omitting suffixes the OPSU series can be tabulated thus: O stood for overseas and left-hand drive variants had an L prefix to the type code, Hence for example LOPSU2.

Customers for the Royal Tiger were found on every populated continent, sales were however particularly high in Europe, the Middle East, South America and Australasia.

In the UK-administered six counties of Northern Ireland the Ulster Transport Authority constructed its own bus and coach bodies on 176 examples whilst cross-border operators Londonderry & Lough Swilly Railway, The Lough Erne Railway and the Great Northern Railway (Ireland) all took Saunders-Roe bodied PSU1 Royal Tigers, all to the rarer 7 ft 6 in (2,286 mm) width:[11] CIÉ, the Irish Republic's government transport undertaking, after evaluating the coach demonstrator, took 8 ft 0 in (2,438 mm) wide PSU1 Royal Tigers with their own bodies, bus and coach, these forming the 200-strong U-class.

The Irish Army also bought a single example, to transport regimental bands, this was also Saunders-Roe bodied it has a centre entrance is 7 ft 6 in (2,286 mm) wide, registered ZU5000 and delivered in 1953; it has recently been found by preservationists and is now stored awaiting restoration.

[15] Other early territories to take large numbers of overseas Royal Tigers were Australia, Egypt, Finland, India, Iran, Israel, Kenya, New Zealand, Nigeria, Portugal, South Africa, Spain, The Netherlands, and Uruguay.

Thus in 1952 Leyland launched a bus to the concept of the Royal Tiger but with a lighter-weight frame and units standardised with the Comet 90 medium-weight lorry.

Between 1961 and 1964 they converted at least 20 Royal Tiger chassis to the full-length allowed by a recent change in the law, for a cost of £200 for the conversion work; these all received new registrations and a stretch in the wheelbase to 18 ft 6in, Gleave then sent the coach chassis to Scarborough for new 36 ft Plaxton Panorama bodies (one for Harrison of Morecambe, was shown at the 1962 Blackpool Coach Rally with the apt dealer re-registration 2048LG[31])(Audlem was covered by the Cheshire county vehicle licensing office whose index marks included LG[32]).

The home market Royal Tiger also lacked the air-servo assistance to the clutch or gearchange that the OPSU had and as a result clutch pressures were heavy and gear-lever throws were rather long, un-assisted steering was hard to move at low road-speeds, interviews with drivers of the Royal Tiger show they regarded the type as hard work to drive, but rewarding.

A number of Royal Tigers are preserved, both bus and coach, in the southern hemisphere as well as the UK, at least one Les Gleave ‘stretched’ example among them, but the oddest preserved Royal Tiger might be JVB908, new to Homeland Tours of Croydon which carries a Mann Egerton body to Crellin-Duplex patent ‘Half-deck’ pattern; this carries 50 coach seats in facing pairs interlaced above and below a central gangway, it has recently been restored for its private owner by the Scottish Vintage Bus Museum.