The little push-button phone pictured above does not look particularly special, but it forms an important part of British Telecom's advertising history.

In 1980, the telecommunications department of the Post Office became British Telecom, and in 1981 BT became a totally separate public corporation. The 1980s saw many changes in telecommunications in the UK - with the arrival of easy plug-in phones, phonecards, portable phones and mobile phones.

Push button phones date back to at least the 1960s, but it was not until the 1980s in Britain that the button took over from the dial in popularity.

In the 1980s, BT first offered phones for sale (before that you could only rent them), and produced an exciting new range of phones, including the Viscount and the Tribune.

The Tribune phone arrived in 1987, and was available in several colours. There was a choice of bell ring (still quite popular at the time) or electronic warble models.

A modern and functional looking but still attractive phone, a red BT Tribune was used by actress Maureen Lipman (playing Beattie Bellman) in the famous "You Got An Ology?" TV advertisement, which was filmed in 1987.

So, if you're auctioning a red BT Tribune on eBay, it is worth pointing out that model's part in one of the most famous television advertisements, not just of the 1980s, but of all time!

If you study the BT Beattie ads, you will see other 1980s BT phones - including Viscount models and a white Tribune.

But the red Tribune was the one used by Beattie in that first legendary ad, and that fact could be a selling point for you.

And remember - "you get an ology, you're a scientist..."