The World Trade Organization's first comprehensive agreement involves an effort to simplify the procedures for doing business across borders.

There will also be improved duty-free access for goods sold by the world's poorest countries.

The deal, which could add about $1tn to world trade, gives developing nations more scope to increase farm subsidies.

"For the first time in our history, the WTO has truly delivered," said WTO chief Roberto Azevedo, as the organisation reached its first comprehensive agreement since it was founded in 1995.

"This time the entire membership came together. We have put the 'world' back in World Trade Organization," he said.

Indonesian Trade Minister Gita Wirjawan said the deal would "benefit all WTO members".

UK Prime Minister David Cameron said the "historic" agreement could be a "lifeline" for the world's poorest people, as well as benefiting British businesses to the tune of more than $1bn (?00m).

However, the package was criticised by some development campaigners who said it was not going far enough.

Rich and poor

It is worth spelling out something what is not covered by this - tariffs or taxes on imported goods.

Dealing with them has been the bread butter of past trade rounds - but not for this deal.

The core of this agreement is what is called trade facilitation. This is about reducing the costs and delays involved in international trade. It is often described as "cutting red tape".

Some analysts suggest the benefits could be large. An influential Washington think tank has put the potential gains to the world economy at close to $1tn and 20m million jobs.

It also estimates the cost of administrative barrier as double the cost of tariffs.