Tour buses are great but they must set an example - Alastair Dalton

They were the bane of my life when I lived in Edinburgh’s Royal Mile many years ago.

Edinburgh Bus Tours carry more than 700,000 passengers a year - 42 per cent more than a decade ago. Picture: Lothian

Audible from our fourth floor windows overlooking the High Street, the regular stream of open-top tour buses chugged slowly past, churning out both diesel fumes and commentary from the guides, amplified by loudspeakers.

I remember mentally classifying them along with the street’s tartan tat shops as among the worst features of tourism in the capital - and thought who else but visitors would want to go on one?

It took some Australian guests to show me the error of my jaundiced thoughts. They sang the praises of tour buses - and even persuaded me to join them on board.

I immediately realised I had misjudged the experience, and thoroughly enjoyed it. Travelling on the top deck of any double-decker gives passengers a unique perspective, but tour buses are even better.

Not only are many open top, but their routes include streets not covered by regular buses, so you’re given a vantage point of the urban scenery not available any other way - and who isn’t up for a peek through the upper floor windows of those grand New Town townhouses?

I had also not realised, being a resident, that tour buses are a great way to get an introductory overview of a city. They are consequently now pretty much top of the to-do list when I’m visiting a new place.

Tour buses also have the terrific advantage of providing a rest for feet tired from pounding the streets, or a lazy way to get around, however you look at it. This is particularly useful if you’re with young children, too eager to demand being carried at any opportunity.

There are now also tour buses in Oban, Inverness and the Borders, while Glasgow’s will be extended into the evening this summer, it was announced yesterday.

Tour buses have been a particularly big success in Edinburgh, becoming one of the capital’s most popular attractions in their own right.

Lothian, which has cornered the market over many years, carries more than 700,000 passengers a year on its four tour routes - up 42 per cent on a decade ago.

Rivals First, seeing an opportunity, is launching its own open-top tours next month with tickets a third less than Lothian’s.

But while competition might be good for tourists’ pockets and spur quality improvements, there have been justifiable concerns raised about yet more buses piling into Edinburgh’s congested and polluted city centre.

Buses are among the most polluting forms of road transport, and significantly, while Lothian said its tour bus fleet all had the cleanest-rated diesel engines, this is not the case with First’s vehicles.

Their engines are Euro 4 standard, which are legal but have higher emissions than Lothian’s Euro 6 tour buses. First said its buses were “future proofed” by being capable of being upgraded or retrofitted to comply with Edinburgh’s planned low emission zone.

However, to bring in less than optimal vehicles as part of an attempt to break into the capital’s tour bus market appears opportunistic.

For many passengers, sightseeing tour vehicles will be the only buses they travel on. That underlines the importance of making the best possible impression on those who still need encouragement to become more regular bus travellers - including minimising emissions.