His is the voice that terrorises the screen villain and also cajoles millions of parents across the country to take their children to the nearest polio vaccine booth.

Matinee star Amitabh Bachchan is proving to be the most successful ambassador yet of the drive to eradicate polio, the crippling disease that affects children under five.

Last week's polio immunisation drive in the country saw parents all over India trudging to the nearest booth to give their child the two drops of the vaccine that helps in immunising against the disease for which there is no cure. And most of them said they had been convinced by Bachchan's exhorting them to do so on TV spots and radio commercials.

"In as many as 70 percent of the cases of people who came to the polio booths, the respondents admitted that Amitabh Bachchan had been the prime motivator in them bringing their children for immunisation," said Brent Burkholder, WHO regional advisor immunisation and vaccine development for Southeast Asia.

The numbers are truly astounding.

The scale of the polio vaccination drive being undertaken in India is unparalleled - with 165 million children being reached across in a single day.

For several months now, as brand ambassador for Unicef's coordinated polio campaign for the health ministry, Bachchan has been seen -- and heard -- scolding, reasoning and pleading with parents to help India become polio free.

He has glamorous help, of course. In a recent TV spot, an exasperated yet amused Bachchan tells the people that he will have to call a fairy -- and in walks the beautiful Aishwarya Rai to add her voice to the polio cause.

Sports icon Sachin Tendulkar is also part of the campaign with Bachchan.

But clearly Bachchan is the one who scores in India's vast rural countryside and urban settlements.

While Bachchan works his magic on the screen, millions of volunteers slave hard behind to make eradication of polio a reality.

Around three million volunteers, many of whom trudge door-to-door in remote areas to administer the polio drops right at the doorstep, are involved in the mammoth exercise to help India achieve its target of becoming polio free by the end of this year.

"Besides the problem of resistance (due to ignorance and religious beliefs), logistics is the bigger issue in India.

"Of the estimated 165 million children targeted, around 95 percent of the target was reached in the last round on April 4," said Burkholder.

So far this year, India has held three national polio immunisation drives in January, February and in April.

The next round will cover 135 million in states like Uttar Pradesh and Bihar, where some of the areas are still uncovered.

"A careful record is being made of the area left uncovered in the last round due to logistical reasons. In key areas like Uttar Pradesh and Bihar, these houses will also be covered.

"Similarly, special efforts will be made in Karnataka, Andhra Pradesh and Tamil Nadu where some cases were reported last year," said the WHO official.

India is among the last six countries including Pakistan, Nigeria, Niger, Egypt and Afghanistan where polio has been reported in 2004. Of the 51 cases reported globally so far, India accounted for eight cases.

India's neighbour Bangladesh has been free of polio since 2000. For a country to be declared polio free, no case should be reported for three consecutive years.

In recent years, the highest number of cases in India was in 2002 when the numbers soared to 1,600, with the majority of cases in Uttar Pradesh and Bihar. The following year, the number fell to 225.

As most of the polio cases are reported post-monsoon in the winter months, extra surveillance is being mounted. The effort is to ensure that every child below five gets at least four to six doses of polio vaccination for better immunity.

"Lot of resources are being put in by Unicef, WHO and the Indian government to ensure that polio is eradicated. We are cautiously optimistic that the target will be achieved," said Burkholder.

Two more national rounds of immunisation are slated to be held in November and December, the months when most cases have been reported in the past.