  As Autonomous Systems (AS) become more ubiquitous in society, more
responsible for our safety and our interaction with them more frequent, it is
essential that they are trustworthy. Assessing the trustworthiness of AS is a
mandatory challenge for the verification and development community. This will
require appropriate standards and suitable metrics that may serve to
objectively and comparatively judge trustworthiness of AS across the broad
range of current and future applications. The meta-expression `trustworthiness'
is examined in the context of AS capturing the relevant qualities that comprise
this term in the literature. Recent developments in standards and frameworks
that support assurance of autonomous systems are reviewed. A list of key
challenges are identified for the community and we present an outline of a
process that can be used as a trustworthiness assessment framework for AS.
