Study endpoints: Primary: Percentage of time spent in euglycaemia. Secondary: percentage of time spent in hypoglycaemia and hyperglycaemia, incidence and severity of hypoglycaemia (as measured with SMBG), incidence of adverse effects, number of measurements of blood glucose (SMBG) performed, number of adjustments of insulin therapy, patient satisfaction, agreement of paired SMBG and RT-CGMS measurements.