Iran's resumption of full diplomatic ties with Britain is more evidence that Tehran is coming in from the cold in its relations with the West and some of its Arab neighbors, but there is one major exception - the United States.

Iran's Islamic Revolutionary regime launched an aggressive campaign to woo the West earlier this year after Iraq gained dominance in the 8-year-old Persian Gulf war. The new policy began to bear fruit almost before the ink was dry on a cease-fire agreement signed by the two adversaries in August.However, Iran has maintained its public depiction of the United States as "the Great Satan."

Iran was one of only a few nations that did not send a congratulatory message to Vice President George Bush on his election as president Tuesday, and official Tehran Radio said Thursday that Washington must return several billion dollars in frozen Iranian assets before any resumption in relations with the United States could occur.

Washington has insisted that diplomatic prog-ress is impossible until Iran moves to help free nine Americans held hostage in Lebanon by Iranian-backed guerrilla groups.

Britain, however, agreed to renew normal relations Thursday after nearly a decade of strained ties without having first gained the release of its three hostages in Lebanon, including Church of England envoy Terry Waite, or even freedom for two Britons imprisoned in Iran.

There were reports that the two sides discussed the hostages' fate in the Vienna negotiations that led to the resumption of full relations. As part of the agreement, Iran pledged not to discriminate against British businesses in Iran and cooperate in the case of the two Britons in an Iranian jail.

The near break in British-Iranian relations began in May 1987, when an Iranian diplomat in Manchester, England, was caught shoplifting. Shortly afterward, Iranian Revolutionary Guards in Tehran kidnapped and beat up British diplomat Edward Chaplin, who was subsequently released.

After the incident, Britain withdrew its entire staff from Tehran, and Iran left only one representative in London. The two nations stopped just short of breaking off diplomatic ties.

Iran launched its opening to the West at the height of the Persian Gulf war, when the Islamic power found itself isolated diplomatically after a series of disputes with Middle East and European countries.

The first success for Iran's new approach occurred with France.

Using the French presidential elections in May as a political backdrop, Iran worked out an agreement to release the remaining two French hostages in Lebanon in exchange for the restoration of diplomatic ties and the paying off of a $1 billion loan made by the former regime of Shah Mohammed Reza Pahlavi.

Since the cease-fire was signed in August, Kuwait has renewed ties and icy relations with Saudi Arabia have begun to thaw.