George Canning's agreement to send troops to Portugal, to counteract Spanish threat of invasion in support of Dom Miguel, who is trying to obtain throne from Maria.
Editors. "Britain supports Portugal against Spain by sending troops to Tagus". The Literary Encyclopedia. First published 01 January 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=4632, accessed 31 January 2015.]