King Charles and Keir Starmer welcomed Qatar's emir, Sheikh Tamim bin Hamad Al Thani, for a state visit to Britain on Tuesday that the prime minister hopes will help build on the Gulf state's investment in the country. The emir and wife Sheikha Jawaher bint Hamad bin Suhaim Al Thani arrived by car at Horse Guards Parade in London with Prince William and his wife Kate, who was marking her return to formal state visit duties after undergoing preventative chemotherapy for cancer. Charles, who is continuing his own treatment for cancer, and the emir inspected the 1st Battalion Welsh Guards while a military band played. Britain is seeking deeper ties with the wealthy Gulf state, and Starmer hopes to use the visit to secure "tangible benefits" for the country on security and the economy, his spokesperson said. Qatar is already a big investor in Britain through the Qatar Investment Authority. A state banquet will be held in the evening.