London Underground made a fresh pay offer to rail unions today in a bid to head off a two-day strike next week that threatens to bring travel chaos to millions in the capital, according to Reuters. London Underground bosses said they had made a revised four-year offer of 1.5 percent this year and 0.5 percent above inflation for the next three years. They also tabled an alternative two-year offer of one percent this year and inflation plus 0.5 percent next year. The RMT members plan to walk out for 48 hours from 7 p.m. (1800 GMT) on Tuesday over a demand for a five percent increase this year. Rail chiefs called the new offer a "very fair" one in tough economic times. "There is now no reason whatsoever for the RMT leadership to continue to call for strike action next week," said London Underground interim managing director Richard Parry. "This is a very fair offer which we urge all of the unions to seriously consider and put to their memberships," he said.