Top British media outlets say President Lee Myung-bak's response measures to the "Cheonan" incident signal a deliberate change in how Seoul deals with North Korea.

The Internet edition of The Times detailed Lee's call for a North Korean apology and a punishment of those responsible for the attack as well as a complete halt to inter-Korean trade and the resumption of psychological warfare against the North.

The BBC said the measures announced by South Korea are the strongest that can be taken outside of a military response. It forecast that the moves will deal a heavy blow to North Korea, noting that Pyongyang depends on South Korea and China for 80 percent of its trade and 35 percent of its gross domestic product.

The Telegraph, meanwhile, said in its online edition that South Korea's share prices and currency value dipped somewhat following Lee’s announcement but later recovered a little, as traders appeared to signal that the situation was not yet sufficiently grave to trigger capital flight.