The move marks the clearest sign yet that Mr Green seeks to expand further in the commercial television market in the UK, following liberalisation of ownership rules under the new Broadcasting Act. If Carlton goes ahead with the takeovers, and if Granada moves, as expected, to acquire Yorkshire- Tyne Tees, the northern ITV franchise holder, two companies will end up owning half the ITV licences in the UK.
Granada, the media and leisure giant, already holds the licences for London Weekend and the North-west of England, while Carlton owns the London weekday and Central licences.
According to informed sources, Carlton sought indications from the Independent Television Commission about whether the 25 per cent limit on share of television advertising would be rigorously applied. Carlton's sales house already accounts for about a quarter of all ITV advertising slots.
It is understood that the ITC will hold fast to the ceiling, but has conceded that the launch of Channel 5 early next year is likely to reduce the advertising share accruing to Carlton, thus freeing it to expand further.
A bid for HTV has been expected for several months, but Mr Green has made it clear he does not intend to over-pay. Takeover speculation has pushed HTV's shares sharply higher in the past year. They closed on Friday at 336.5p, equivalent to more than 30 times expected 1996 earnings.
Granada, too, has held back from making a full bid for Yorkshire-Tyne Tees, which is currently trading at well over pounds 12 a share. It is expected that the two predator companies will wait to see whether the takeover premiums attached to HTV and YTT subside in coming months.
A bid for HTV by Carlton could be accompanied by an offer for Westcountry, media analysts speculated over the weekend. Indeed, it is considered possible that HTV may bid for Westcountry on its own before a Carlton approach materialises. That possibility was thought to be behind Carlton's request for ITC guidance on both HTV and Westcountry.
Westcountry, owned by the Daily Mail & General Trust, Brittany Ferries and South West Water, has appointed Lazard Freres, the merchant bank, to help it prepare for a possible flotation. However, the Independent has learned that Lazards has approached other ITV companies about engineering a trade sale. Lazard executives visited HTV on Friday to discuss the possibility of an agreed bid for Westcountry.
HTV and Westcountry together represent about 8 per cent of total ITV advertising sales. Their ad business is handled by TSMS, the sales house owned by United News & Media, Lord Hollick's print and television conglomerate.
Carlton has attempted to take advantage of HTV's dissatisfaction over its arrangements with TSMS by suggesting it could do a better job of selling HTV's advertising time. A Carlton sales insider insisted late last week, however, that any deal to shift HTV's business from TSMS to Carlton would only be possible once Channel 5 was up and running.
"The rules wouldn't allow us to do it now," the source said. "In any event, such a deal would be made redundant by a takeover of HTV by Carlton."
UNM was a wild card in the current climate, media analysts said. "It cannot afford to lose the HTV and Westcountry business," said one.
As a consequence, Lord Hollick might also emerge as a bidder for HTV, in a bid to safeguard its ad sales arrangements.
"He will want to emerge as the second bidder," said one senior ITV source. "The best scenario for Hollick is to wait for Carlton to move, and then to present himself as the white knight."