There is a limit to the patience of the international community with the Assad regime in Syria, Foreign Secretary William Hague warned on Monday.
However, the attitude of the Russians and Chinese remains a "constraint" on what can be done, he said.
Hague, launching in London the Foreign Office's guide to human rights and democracy around the world, said the government remained "gravely concerned" about the situation in Syria.
"The regime is not fully implementing the terms of the ceasefire, people continue to be killed, although the violence is not on as great a scale as it was before 12 April.
"It is very clear that the Assad regime has only complied with any of the terms of the ceasefire under duress, and is not being as helpful to the work of the monitors as it should be.
"Clearly this cannot go on indefinitely, there is a limit to the patience of the international community on this."
However, if there was a return to the United Nations there would need to be a change in the position of Russia and China, who had vetoed stronger resolutions, "so that remains a constraint on what we can do".
He was asked about a French call for a tougher stand, and said other countries would put different options on the table.
Meanwhile Britain was already increasing support for non-lethal activity by Syrian opposition groups.
Hague said the Syrian regime was determined to cling to power but was doomed in the longer term.
He said 2011 would stand out as a positive year for human rights and democracy, and praised the courage shown by people in Syria, Tunisia, Egypt and Libya.
"They have sent a chill down the spine of undemocratic regimes far beyond the Middle East," he said.
"2011 saw successful Nato intervention to save lives in Libya, and the beginning of what we hope will be Burma's irrevocable transformation.
"This country stood by Aung San Suu Kyi for so long, and we did not do this in vain.
"We are now leading the way in suspending sanctions, lifting policies of discouraging trade with Burma.
"2011 was a year in which the cause of democracy and freedom was ignited more than any other year I can remember since the fall of the Berlin Wall."
He warned that there would be setbacks as well as advances. "But we should not become pessimistic or fatalistic or slip back into old ways of thinking, about the Middle East in particular.
"Our approach also includes constantly striving to live up to our values and address where we fall short."
This included consideration of "past allegations of British complicity in extraordinary rendition leading to torture".
He said the Foreign Office had a dedicated £5 million democracy and human rights budget for the coming year and he was announcing today that it was being boosted by £1.5m to support its work, including seeking to protect freedom of expression online.
Hague was asked about the impending visit of the King of Bahrain, and said: "Invitations to the Diamond Jubilee are a matter for the Palace, not government decisions, but I understand all sovereigns of countries with which we have diplomatic relations are being invited.
"We have concerns about Bahrain, but I wish other countries had international commissions of inquiry."
The report says the Bahrain Independent Commission of Inquiry had a "credible and independent membership" and steps had been taken to implement reforms based on its recommendations.
But it noted that violent clashes continued, and urged full implementation.
Hague was also asked if he was ready for "dialogue" over the Falkland Islands, and he said: "Self-determination is a basic political right of the people of the Falkland Islands, and they can count on us always, permanently, to stand by them."