The family of missing Katrice Lee are marching to Downing Street in London to mark the anniversary of her disappearance in 1981.
Katrice was two years old when she went missing from a NAAFI supermarket in Germany where her father, Richard Lee, was stationed at the time.
The toddler disappeared on her birthday over thirty years ago and has not been seen since.
The case of missing Katrice was brought the parliament earlier this month when MPs debated how the case had been handled.
The government had previously promised to do all it could to get the family from Teesside more information about their daughter's disappearance.