* 2012 payout of 19 pence vs 25.6 pence consensus
* Underlying op. profit down 4.3 pct at 1.77 bln stg
* Shares down 13 percent, top FTSE faller
* Directors to get no bonus, no pay rise
LONDON, March 7 (Reuters) - British insurer Aviva slashed its 2012 dividend by more than a quarter to repay debt, sending its shares tumbling 13 percent, and drawing unflattering comparisons with a windfall payout from rival Standard Life .
Aviva shareholders will get 19 pence from 2012 earnings, compared with 26 pence the previous year, and well below the 25.6 pence forecast by analysts in a company poll, the insurer said on Thursday.
""This was a difficult decision, but it was absolutely necessary to give certainty to our shareholders, to reduce debt, and to put Aviva on a sound footing for the future," Aviva Chief Executive Mark Wilson told reporters, adding that he and other top executives would get no bonuses or pay rises this year.
The dividend cut, Aviva's second in four years, came as the company reported a 15 percent drop in operating profit to 2.13 billion pounds, broadly in line with forecasts.
Standard Life said it would pay investors a special dividend of 302 million pounds, on top of a 6.5 percent increase in the regular payout, after forecast-beating profit growth last year contributed to a "very strong" capital position.
Shares in Aviva were down 13 percent by 1050 GMT, the steepest faller in the FTSE 100 share index.
That wiped 1.3 billion pounds ($1.96 billion) off the company's value, relegating it to fourth position from second in the ranking of British insurers by market capitalisation, behind Old Mutual and Legal & General. Old Mutual and Legal & General both announced divided hikes for 2012.
"Aviva has the worst dividend paying record of all the major UK life companies, and it will clearly take some considerable time to persuade investors that the latest management team have got it right," said Investec analyst Kevin Ryan.
The dividend cut is the latest step in a reorganisation launched by Aviva last July after investors irked by a persistently weak share price forced out Wilson's predecessor, Andrew Moss.
Under the plan, the insurer has cut costs and raised about 2.4 billion pounds by selling less profitable businesses that tie up too much capital, including its subsidiary in the United States.
That helped double Aviva's capital surplus to 7.1 billion pounds by the end of 2012, addressing investor concerns that the insurer did not have strong enough cash reserves given its heavy exposure to the troubled euro zone, Wilson said.
But the disposals also boosted Aviva's debt as a proportion of assets, putting it under pressure to repay what it owes more quickly.
Wilson, formerly head of Asian insurer AIA, said Aviva now aimed to generate more cash from its flagship British and Canadian businesses while investing in units with good growth potential, including its Polish, Turkish and Asian arms.
"The insurance sector has made an industry out of complexity," he said.
"We need to be simple, we need to be understandable, we need to be as dependable as a Swiss clock, and that is my promise."
One of the European insurance sector's main attractions for stock market investors is its ability to pay relatively big dividends, reflecting its predictable revenues as customers renew their policies annually.
Standard Life announced a 2012 operating profit of 900 million pounds, up 65 percent, exceeding the 400 to 600 million target set out in its directors' long-term incentive plan, and entitling them to the maximum payout under the scheme, Chief Executive David Nish said.