Beijing has attached growing importance to Sino-Europe relations in recent years, as evidenced by the timing of Wen's latest trip, which came just two months after he went to France, Spain and Portugal. Other senior officials, such as Vice-Premier Li Keqiang, visited Britain last year.

Dr Thomas Heberer, a Germany-based expert on East Asian studies, said that with the US playing a dominant role in world affairs, Beijing was looking to strengthen global ties.

'China needs a friend and partner other than the US, and clearly Europe is the only one that might ... be a challenge to the US. So China needs to have a good relationship with the US on one side, but a good relationship with Europe as well on the other side,' Heberer said. 'If necessary, China can counterbalance both.'

Wen expressed confidence that Europe could fend off its sovereign debt crisis. He also stressed that Beijing wanted to establish trust with Europe, and he urged Europe to show similar intentions by calling for an end to an arms embargo and restrictions on hi-tech exports to China.

Following the billion-dollar signings, Ralph Rogers, China business adviser for the China-Britain Business Council, said he expected Sino-British investment to rise.

And Josef Janning, director of studies at the European Policy Centre think tank in Brussels, said both Europe and China largely got what they wanted from Wen's tour. 'A deeper partnership ... is emerging. And there is a general recognition that the best way to deal with China is to respect the comprehensive challenge that China is going through,' he said.

However, Steve Tsang, director of the China Policy Institute at the University of Nottingham, said Beijing had not offered much help. 'China bought some Greece bonds, but they are not doing it now,' he said. 'China is just buying the bonds for cheap, and it runs in the interests of China.'

But even though Europe can trust China more on trade issues and support for the debt crisis, analysts say, Europeans will still be sceptical about its political environment. Britons and Germans said their impression of China was adversely affected by the April arrest of artist-activist Ai Weiwei , who was released two days before Wen left for Europe on Friday.

At the Royal Society in London, and at a meeting with the Chinese community in Berlin, Wen admitted China faced many social problems despite 30 years of economic boom. He called for the implementation of reforms that would let citizens monitor and criticise the government.

'Europeans will welcome that [political reform] and will watch what happens,' Janning said. 'In Europe, there is a fairly high understanding of how complicated that is ... I think Europeans remain a bit sceptical because they know it is difficult. They know it is not a matter of declaration to get it done.'

European officials said they would keep pressing Beijing to improve human rights.

Nevertheless, political issues are unlikely to affect Sino-Europe ties.

Germany, once very critical of China's rights environment, softened its tone in 2009 as it needed Beijing's support in the financial crisis, Heberer said. 'Economic issues take a strong priority over political and social issues,' he said. 'Governments in Europe know it is useless to stress human rights every time they meet.'