The strip was launched in London's Evening Standard newspaper. Since London papers were national in scope, syndication opportunities in the United Kingdom were limited and that was a constraint on British strips -- potential income streams were limited compared to those in the continent-wide American newspaper scene.
Nevertheless, Modesty Blaise caught on, largely due to Holdaway's art, and it was syndicated in many parts of the Commonwealth as well as in the USA.
Holdaway combined skilled representational drawing with the ability to compose a variety of dramatic viewpoints even in one three-panel strip. His basic approach was to include strongly shaped areas of pure black with thin pen or brush lines. He also made use of cross-hatching and sometimes even downplayed the black if that suited the scene he was depicting.
Below are some sample strips grabbed from various Web sites intended to give you a sense of what he accomplished. Click on them to enlarge.