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* Indian PM in Britain from Nov. 12-14
* Modi seeks to bounce back from state election drubbing
* Some party bosses question his leadership
* Modi to address huge crowd at Wembley Stadium
By Andrew MacAskill and Sanjeev Miglani
NEW DELHI, Nov 11 (Reuters) - Indian Prime Minister NarendraModi will address a mass rally on a visit to Britain this weekthat supporters hope will help him spring back from ahumiliating election loss and reassert his authority on theglobal stage.
India and Britain could announce deals worth 8-12 billionpounds ($12-$18 billion) during the visit, according todiplomats, with Modi keen to buy 20 more BAE Systems Hawk trainer aircraft to be made in Bengaluru.
Britain is home to an Indian diaspora of 1.5 million, andthe two nations share the English language, historical ties andan obsession with cricket. Yet Modi has, in his first 18 monthsin power, made a priority of courting global powers like theUnited States and China.
"UK-India ties are economically strong, but strategicallyweak," said Shashank Joshi, a senior research fellow at theRoyal United Services Institute in London.
Seeking to regain the initiative after crashing to defeat ina big state election at the weekend, Modi eased foreigninvestment rules this week in 15 sectors, including mining,defence and civil aviation.
"By introducing these reforms the government is certainlyspelling out why India is an attractive destination," said NalinKohli, a spokesman for Modi's Bharatiya Janata Party (BJP).
The centrepiece of the Nov. 12-14 trip will be a mass rallyand firework display at Wembley Stadium on Friday for anestimated 60,000 supporters - three times bigger than the crowdhe drew to New York's Madison Square Garden last year.
Yet Modi's popularity is being challenged at home. The BJPlost an election badly in the eastern state of Bihar, home to104 million people, and for the first time party leaders areopenly questioning the direction of his government.
REVAMP SOUGHT
British Prime Minister David Cameron is seeking to revampeconomic ties with fast-growing Asian nations, including India,as part of his push on business-focused diplomacy.
Modi's trip marks a remarkable turnaround for a man who wasbanned from Britain for 10 years over his alleged role as chiefminister of Gujarat in riots that killed about 1,000 people in2002.
Britain ended a boycott of Modi three years ago after heemerged from being a provincial politician to the likely leaderof the world's largest democracy. He has denied wrongdoing andwas exonerated by an inquiry ordered by India's Supreme Court.
His three-day visit is likely to be marked by protests overthose riots and concerns over recent incidents in India whereMuslims have been targeted by Hindu extremists.
Several groups were planning demonstrations outside WembleyStadium during the rally and near Cameron's Downing Streetoffice to coincide with Modi's visit there.
About 45 British lawmakers, including opposition leaderJeremy Corbyn, recently signed a parliamentary motion to debateIndia's human rights record.
Modi has also attracted negative coverage in the Britishpress, with the left-leaning Guardian newspaper branding him a"divisive manipulator who charmed the world".
The Financial Times predicted his visit would beovershadowed by troubles at home including "a surge of sometimesviolent Hindu chauvinism and a slowdown of economic reform".
However, many in Britain's Indian diaspora were eager tocelebrate Modi, with a website called "UK welcomes Modi"promising to deliver "the loudest, greatest and most vibrantwelcome he has seen outside of India" at the Wembley rally.
Modi's bilateral visit, the first by an Indian primeminister since 2006, follows a pomp-laden visit the Britishgovernment gave China's President Xi Jinping last month thatyielded $62 billion of deals.
Britain has gradually lost ground to other nations in aneffort to increase trade with its former colony. In 2000, it wasIndia's third-largest trading partner. Since then Britain hasslipped to 18th, behind Belgium and Kuwait.
"There is a sense of things being jaded between the twocountries," said Neelam Deo, a former diplomat and director ofGateway House. "For India, Britain is a middle-ranking power -it doesn't seem to have an independent foreign policy." (Additional reporting by Estelle Shirbon in London; Editing byMike Collett-White)