<PAGE>

                                POWER OF ATTORNEY

         The undersigned officer and/or director of Sopheon plc hereby
constitutes and appoints Barry K. Mence and Arif Karimjee, or either of them,
with power to act one without the other, his true and lawful attorney-in-fact
and agent, with full power of substitution and resubstitution, for him and in
his stead in any and all capacities to sign the Form F-4 Registration
Statement of Sopheon plc relating to the acquisition of Teltech Resource
Network Corporation, and any and all amendments to such Registration
Statement, pursuant to the requirements of the Securities Act of 1933, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorney-in-fact and agent, full power and authority to do and perform each
and every act and thing necessary or advisable to be done in connection
therewith, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorney-in-fact and
agent, or his substitute or substitutes, may lawfully do or cause to be done
by virtue hereof.

   Dated: August 8, 2000
                                          Signed: /s/ Stuart Silcock

                                          Name: S. A. Silcock
<PAGE>

                                POWER OF ATTORNEY

         The undersigned officer and/or director of Sopheon plc hereby
constitutes and appoints Barry K. Mence and Arif Karimjee, or either of them,
with power to act one without the other, his true and lawful attorney-in-fact
and agent, with full power of substitution and resubstitution, for him and in
his stead in any and all capacities to sign the Form F-4 Registration
Statement of Sopheon plc relating to the acquisition of Teltech Resource
Network Corporation, and any and all amendments to such Registration
Statement, pursuant to the requirements of the Securities Act of 1933, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorney-in-fact and agent, full power and authority to do and perform each
and every act and thing necessary or advisable to be done in connection
therewith, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorney-in-fact and
agent, or his substitute or substitutes, may lawfully do or cause to be done
by virtue hereof.

   Dated: August 10, 2000
                                          Signed: /s/ Hans Coltof

                                          Name: Dr. Hans Coltof
<PAGE>

                                POWER OF ATTORNEY

         The undersigned officer and/or director of Sopheon plc hereby
constitutes and appoints Barry K. Mence and Arif Karimjee, or either of them,
with power to act one without the other, his true and lawful attorney-in-fact
and agent, with full power of substitution and resubstitution, for him and in
his stead in any and all capacities to sign the Form F-4 Registration
Statement of Sopheon plc relating to the acquisition of Teltech Resource
Network Corporation, and any and all amendments to such Registration
Statement, pursuant to the requirements of the Securities Act of 1933, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorney-in-fact and agent, full power and authority to do and perform each
and every act and thing necessary or advisable to be done in connection
therewith, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorney-in-fact and
agent, or his substitute or substitutes, may lawfully do or cause to be done
by virtue hereof.

   Dated: August 9, 2000
                                          Signed: /s/ Huub J.M. Rutten

                                          Name: H.J.M. Rutten


<PAGE>

                                POWER OF ATTORNEY

         The undersigned officer and/or director of Sopheon plc hereby
constitutes and appoints Barry K. Mence and Arif Karimjee, or either of them,
with power to act one without the other, his true and lawful attorney-in-fact
and agent, with full power of substitution and resubstitution, for him and in
his stead in any and all capacities to sign the Form F-4 Registration
Statement of Sopheon plc relating to the acquisition of Teltech Resource
Network Corporation, and any and all amendments to such Registration
Statement, pursuant to the requirements of the Securities Act of 1933, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorney-in-fact and agent, full power and authority to do and perform each
and every act and thing necessary or advisable to be done in connection
therewith, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorney-in-fact and
agent, or his substitute or substitutes, may lawfully do or cause to be done
by virtue hereof.

   Dated: August 9, 2000
                                          Signed: /s/ M. J. Brooke

                                          Name: Michael John Brooke
<PAGE>

                                POWER OF ATTORNEY

         The undersigned officer and/or director of Sopheon plc hereby
constitutes and appoints Barry K. Mence and Arif Karimjee, or either of them,
with power to act one without the other, his true and lawful attorney-in-fact
and agent, with full power of substitution and resubstitution, for him and in
his stead in any and all capacities to sign the Form F-4 Registration
Statement of Sopheon plc relating to the acquisition of Teltech Resource
Network Corporation, and any and all amendments to such Registration
Statement, pursuant to the requirements of the Securities Act of 1933, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorney-in-fact and agent, full power and authority to do and perform each
and every act and thing necessary or advisable to be done in connection
therewith, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorney-in-fact and
agent, or his substitute or substitutes, may lawfully do or cause to be done
by virtue hereof.

   Dated: August 9, 2000
                                          Signed: /s/ James M. Macfarlane

                                          Name: James Malcolm Macfarlane
<PAGE>

                                POWER OF ATTORNEY

         The undersigned officer and/or director of Sopheon plc hereby
constitutes and appoints Barry K. Mence and Arif Karimjee, or either of them,
with power to act one without the other, his true and lawful attorney-in-fact
and agent, with full power of substitution and resubstitution, for him and in
his stead in any and all capacities to sign the Form F-4 Registration
Statement of Sopheon plc relating to the acquisition of Teltech Resource
Network Corporation, and any and all amendments to such Registration
Statement, pursuant to the requirements of the Securities Act of 1933, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorney-in-fact and agent, full power and authority to do and perform each
and every act and thing necessary or advisable to be done in connection
therewith, as fully to all intents and purposes as he might or could do in
person, hereby ratifying and confirming all that said attorney-in-fact and
agent, or his substitute or substitutes, may lawfully do or cause to be done
by virtue hereof.

   Dated: August 23, 2000
                                          Signed: /s/ R.V. Maddocks

                                          Name: Richard V. Maddocks