A steerable instrument having a proximal end and a distal end and comprising at least one steering device arranged at said proximal end, and a tubular body extending in a longitudinal direction along a central axis from said proximal end to said distal end, said tubular body having an intermediate flexible zone and at least one distal deflectable zone, said tubular body including at least one tube element made from a metal, the tube element being provided with a first slotted structure in the flexible zone and a second slotted structure (72; 106; 136; 156) in the at least one deflectable zone, the tubular body being provided with tangential rotation blocking elements arranged such as to form a plurality of cable channels (96; 97; 152), each cable channel (96; 97; 152) accommodating one of a plurality of cables; said cables being connected at said proximal end to said steering device and at said distal end to said deflectable zone to allow deflection of said deflectable zone by means of said steering device; wherein said at least one tube element is an intermediate tube element (88; 88a; 88b; 88d; 88e) which: • is arranged in at least a portion of said tubular body, • has an inner surface and an outer surface, said inner surface surrounding a first channel, • has a cross section structure with a uniform thickness along its entire length; • comprises said second slotted structure to provide said intermediate tube element (88; 88a; 88b;; 88d; 88e) with at least one deflectable section, and • is configured in at least one of the following shapes to provide said tangential rotation blocking means: a. said outer surface has a corrugated cross section along its entire length defining a plurality of first cable channels each one accommodating at least a portion of one cable, and b. said inner surface has a corrugated cross section along its entire length defining a plurality of second cable channels each one accommodating at least a portion of one cable. said tubular body including at least one tube element made from a metal, the tube element being provided with a first slotted structure in the flexible zone and a second slotted structure (72; 106; 136; 156) in the at least one deflectable zone, the tubular body being provided with tangential rotation blocking elements arranged such as to form a plurality of cable channels (96; 97; 152), each cable channel (96; 97; 152) accommodating one of a plurality of cables; said cables being connected at said proximal end to said steering device and at said distal end to said deflectable zone to allow deflection of said deflectable zone by means of said steering device; wherein said at least one tube element is an intermediate tube element (88; 88a; 88b; 88d; 88e) which: • is arranged in at least a portion of said tubular body, • has an inner surface and an outer surface, said inner surface surrounding a first channel, • has a cross section structure with a uniform thickness along its entire length; • comprises said second slotted structure to provide said intermediate tube element (88; 88a; 88b;; 88d; 88e) with at least one deflectable section, and • is configured in at least one of the following shapes to provide said tangential rotation blocking means: a. said outer surface has a corrugated cross section along its entire length defining a plurality of first cable channels each one accommodating at least a portion of one cable, and b. said inner surface has a corrugated cross section along its entire length defining a plurality of second cable channels each one accommodating at least a portion of one cable. • is arranged in at least a portion of said tubular body, • has an inner surface and an outer surface, said inner surface surrounding a first channel, • has a cross section structure with a uniform thickness along its entire length; • comprises said second slotted structure to provide said intermediate tube element (88; 88a; 88b;; 88d; 88e) with at least one deflectable section, and • is configured in at least one of the following shapes to provide said tangential rotation blocking means: a. said outer surface has a corrugated cross section along its entire length defining a plurality of first cable channels each one accommodating at least a portion of one cable, and b. said inner surface has a corrugated cross section along its entire length defining a plurality of second cable channels each one accommodating at least a portion of one cable. a. said outer surface has a corrugated cross section along its entire length defining a plurality of first cable channels each one accommodating at least a portion of one cable, and b. said inner surface has a corrugated cross section along its entire length defining a plurality of second cable channels each one accommodating at least a portion of one cable.