Practically everyone in the world knows Big Ben but hardly anyone realises that as a UK resident you can arrange a free guided tour through your local MP. Just to clarify your understanding the tower, which most people refer to as Big Ben, is actually the Great Westminster Clock Tower and Big Ben is the affectionate name for one of the bells housed within the Clock Tower – officially it is the Great Bell.

The guided tours up Big Ben are given four times a day, five days a week and with only a small number of people taken up on the tour (16 according to the website) you can imagine that places on the tour is extremely difficult to come by and you often need to book at least a few months in advance. Tours take about 75 minutes including the 15 minutes you need to get there before the start of the tour. No photography allowed unfortunately.

In 2009 the bookings were also expected to be even more tough as the Clock Tower was celebrating a double-150 anniversary with both Big Ben (remember – the bell) and the Clock Face turning 150 years old with the clock being about six weeks older than Big Ben.

The start of the tour is at Portcullis House just across the road from the Clock Tower. Entry into Portcullis House involves putting bags and body through a scanner, having your picture taken and a guest pass issued. The guide then takes you under the street across to the bottom of the Clock Tower.

For my tour a big group had apparently cancelled so it was me, three others and a bunch of the apprentices or interns, I would say, who work at the Houses of Parliament. I think the apprentices/interns would also be the ones who, if not give, help with the Houses of Parliament tours.

It is a total of 334 steps to the belfry (which is the peak of your destination – though it is another 59 to the Aryton Light, which is the light located at the top of the Clock Tower which signals when Parliament is sitting.) If this seems like a long climb it isn’t actually too difficult as the guide has plenty of long stops along the way (about four stops on the way up) at reasonable points of the tour. There is also, rather entertainingly, a defribulator on the seventh floor, should the need for one arise.

Your first stop is after about a hundred steps. At this stop you sit in a room with photos and a story board and the guide tells you part of the history of Big Ben and how it came to be developed. This talk lasts for about ten minutes.

The second stop comes about another 80 or so steps after the first where you are given more history.

The third stop is where it gets a bit more interesting. This stop takes you behind the four clock faces and you can walk right around behind all four. You can walk behind all four. The clock faces are lit by loads of bulbs. Each face requires 28 bulbs of giant (energy efficient) lightbulbs costing £150 pounds each but apparently lasting ten years or 60,000 hours. Before the modern era, of course, they used to be lit by gas light.

Some interesting facts: Each hour hand is 2.7m long and weighs 300kg, the minute hands are 4.2m long and weigh 100kg. and finally the hands travel over 190 km a year. The clock hands and clock face I guess are kept pigeon poo free by Hawks!

The final stop is the belfry where the bells are and Big Ben live. Big Ben is supported by four chime bells. The guide makes sure that you are up in time to hear the bells all go off (which will be 10, 12 or 3 o’clock bells depending on when you do the tour) but, considerately, you are given ear plugs for the loudness of the noise.

The walk down is also not without interest. You get to enter the room where they keep the mechanics of the clock. It’s a very hugely complicated looking contraption but the simplest of methods (weights via old pennies) is used to both speed and slow the clock if its getting too far ahead or falling behind. The clock is actually required to be wound every eight days and the bells (whose weights fall to the ground as they chime) have to be wound back up every two days.

The one rule that the clock must comply with is that it cannot lose more than one second every 24 hours. Given that this technology was developed 150 years ago you have to admire the fact it can keep time so well after so long. Most modern watches seem to speed up or slow down at will!

If you live in London its certainly worth getting yourself on to this tour.