* FTSE up 1.2 percent, strong technical support seen
* Vodafone up, AT&T to buy Deutsche Telekom U.S. operations
* Essar falls after results, project delays
By Simon Falush
LONDON, March 21 (Reuters) - Miners, banks and engineers drove gains in Britain's top share index by the close on Monday as hope grew that the nuclear crisis in Japan is easing, while heavyweight Vodafone was boosted by M&A activity.
Mobile operator Vodafone gained 3.6 percent after U.S. group AT&T said it was planning to pay $39 billion for Deutsche Telekom's T-Mobile USA.
Deutsche Bank said the deal was positive for the long-term value of the U.S. market and Vodafone's 45 percent stake in Verizon Wireless. BT was up 2.4 percent.
Engineers, among those hit hardest last week by the flight to safety prompted by a nuclear crisis caused by a massive quake in Japan, were the strongest gainers and were also lifted by positive broker comment.
Enginemaker Rolls Royce rose 3.5 percent, supported by an upgrade by Evolution Securities to "buy".
Weir Group, a supplier of industrial pumps and valves, gained 4.5 percent after Credit Suisse upped its rating to "outperform" on valuation grounds.
The positive broker comment lifted sentiment elsewhere in the engineering sector, with Invensys the top FTSE gainer, up 5.1 percent.
"Investors were waiting for more clarity on the situation in Japan and in Libya over the weekend, and there's been no more bad news," said Lothar Mentel, CIO at Octopus Investments which has 2.3 billion pounds ($3.74 billion) under management, though he said gains were vulnerable.
"It's not a solid situation and another bad explosion at the Fukushima plant would see another sharp sell-off," he said, adding that this poses more risk than the situation in Libya.
The FTSE 100 closed up 67.96 points, or 1.2 percent, at 5,786.09, its third straight session of gains. The index was still down around 4 percent in March.
Banks, which tend to gain strongly when equities are positive, were firmer with Standard Chartered up 1.7 percent and Barclays adding 2.6 percent.
JP Morgan said the 4-6 percent markdown in global equities after the Japanese quake should only be short term "given that loss of activity due to the (Japan) earthquake is likely to be temporary".
It saw value in the insurance and automotive sectors, and said miners and capital goods firms were good plays on emerging markets outperformance and higher commodity prices.
SUPPORT SEEN
Technical analysts said that recent price movements indicated that there would be significant support around the lows reached last week.
"The bounce started from 5600, the 38 percent (Fibonacci) retracement from July's low to this year's high, (meaning) we will probably hold above here for up to a month, said Nicole Elliott, analyst at Mizuho Corporate Bank.
However she said that prices would likely be capped around the 6,000 level as a head and shoulders pattern is formed.
Oil prices, which rose over 1 percent, were also seen as a potential brake on equity strength, analysts said.
Western powers continued air strikes in Libya, threatening supplies in the Middle East region.
India-focused refiner and power generator Essar Energy fell 7.3 percent after saying a number of key power projects would be delayed, overshadowing full-year earnings which beat forecasts. (Additional reporting by David Brett; Editing by David Cowell)