Rob Howley: Wales interim coach should be number one elsewhere - Williams
Martyn Williams believes Rob Howley should leave Wales' coaching team to gain experience if he wants to succeed Warren Gatland in 2019.
Howley guided Wales to three wins from four Autumn internationals with Gatland focusing on British & Irish Lions duty.
But former Wales captain Williams says a spell in charge of a club side would benefit Howley's future prospects.
"I don't think Rob can be number one without being a number one elsewhere first," Williams told Scrum V.
"He hasn't had the experience of being the main man. Yes he is at the moment but you've got the shadow of Gatland over you.
"He should go and learn his trade at a club and then come back."
New Zealander Gatland, 53, plans to step down as Wales head coach after the next Rugby World Cup in Japan in 2019.
Williams, who played alongside Howley for Wales and Cardiff, cited England's Eddie Jones and Joe Schmidt of Ireland as head coaches who had gained experience with clubs prior to taking charge of national teams.
Former Wales scrum-half Howley has been part of Gatland's coaching team since 2008 having previously been assistant coach of Cardiff Blues.
The 46-year-old will remain in interim charge of Wales for the 2017 Six Nations as Gatland concentrates on his role as British and Irish Lions head coach ahead of next summer's tour to New Zealand.
Howley performed a similar task in 2012-13 when Gatland took a sabbatical to guide the Lions to a 2-1 series win against Australia.
Wales, under Howley, were heavily criticised following their opening defeat by Australia and unimpressive displays in wins over Argentina and Japan.
But they ended the autumn series with a 27-13 win over South Africa.